The feed rate at which a defect free friction stir weld can be run (friction stir weldability) on an HSLA steel plate can vary widely between heats that meet the same specified physical properties. Consequently, every time a new heat of HSLA steel is obtained, exploratory welds must be run to determine the proper feed rate for that plate. Previous research suggests that the varying levels of alloying elements related to high temperature physical properties between the different heats causes the observed change in friction stir weldability. Because of this, it was hypothesized that the high temperature physical properties of HSLA steels are related to their friction stir weldability.High temperature physical propeties of HSLA steels are a function of the alloying content of the steel. To determine the relationship between high temperature physical properties and alloying content, eight different heats of HSLA steel with different chemical compositions were obtained. In particular, percent additions of molybdenum, vanadium, niobium, and titanium were varied between the heats in a factorial design. Gleeble compression tests were run on each heat to determine their high temperature properties. Based on these tests, experimental models wereconstructed to estimate the high temperature properties of HSLA steels based on composition and temperature. These models were used to determine the high temperature physical properties of HSLA heats with known friction stir weldability. The high temperature physical properties werecompared to the friction stir weldability of each heat. No correlation was found in this study between the high temperature properties examined and friction stir weldability in HSLA steels.

The mechanical properties of components made by PM steels are normally inferior to those made by alternative processes. One of the main reasons is that a large amount of pores are present in sintered components. The other main reason is that the alloying elements, particularly Ni, are not uniformly distributed after conventional sintering procedures.  This work is aimed at a better understanding of the influence of alloying additions on mechanical properties and homogeneity of the microstructure. The experimental work has been carried out in two trials. Trial 1 was performed to investigate mechanical properties of Distaloy powders (commercial grades) and second trial to examine influence of alloying additions on homogeneity of microstructure.  For trial 1, as-sintered and heat treated specimens were produced by mixing commercial powders with two different carbon levels. Whereas, alloying elements were admixed to base iron powder for producing  sintered specimens for trial 2. Mechanical properties including dimensional changes, micro-hardness, tensile strength and impact resistance were measured. Distribution of alloying elements was studied using LOM and SEM-EDS analysis. The results obtained show that additions of alloying elements enhance the mechanical properties. Moreover, interaction of C with Cu and Ni as well as interaction between Cu and Ni have a deceive role in determining final properties of the components. The metallographic investigation indicated that major reasons of heterogeneous microstructure are slow diffusion of Ni in Fe matrix and interaction of other alloying elements with Ni.  The results of trial 2 showed that addition of Mo and Cu to Ni-containing PM steels improves the distribution of Ni in Fe matrix. Mo results in improved uniformity of microstructure by lowering the chemical potential of carbon. In Ni and Cu containing alloys, the interaction between Ni and Cu is responsible for enhanced distribution of Ni. However, the improved Ni distribution is achieved at the expense of non-uniform distribution of Cu. In Ni-containing PM steels, improved microstructure homogenization can be attained by increasing Ni-Cu interaction, lowering the surface energy of Ni-Cu liquid and decreasing the chemical potential of carbon.

Os ímãs permanentes de terras-raras tem um papel relevante na indústria de dispositivos eletromagnéticos, principalmente no que se refere à produção de motores para veículos híbridos e elétricos e geradores para turbinas eólicas. Com a recente restrição chinesa a exportação de terras-raras, os altos preços e a necessidade de substituição do Dy nesses ímãs, há um interesse mundial por alternativas a essas questões. A adição de elementos de liga em ímãs permanentes de terras raras tem como objetivo a melhora das propriedades magnéticas. O presente trabalho avalia a influência do Ti, V, Cr, Ni, Zr, Nb e Mo na microestrutura e nas propriedades magnéticas de ímãs sinterizados. Os ímãs foram preparados via metalurgia do pó, a partir de pós obtidos pelo processo de decrepitação por hidrogênio (HD). Na produção do ímã Pr16Fe66,9Co10,7B5,7Cu0,7, sem adição de elementos de liga, foi utilizada a mistura das ligas Pr20Fe73B5Cu2 (33% em peso) e Pr14Fe64Co16B6 (67% em peso). Para avaliar a influência das adições foi utilizada a liga Pr14Fe64Co16B6M0,1, onde M = Ti, V, Cr, Ni, Zr, Nb e Mo (67% em peso). As ligas utilizadas e os ímãs produzidos foram caracterizados por Microscopia Eletrônica de Varredura (MEV) e Difração de Raios-X (DRX), e as propriedades magnéticas foram obtidas por meio de Permeâmetro. O ímã com adição de Cr (iHc = 836 KA.m-1) apresentou coercividade intrínseca 11,8% superior ao ímã sem adição de elemento de liga (iHc = 748 KA.m-1). A maior remanência foi observada para o ímã com adição de Nb (Br = 1,04 T). Os ímãs com as adições de Ti, V e Zr apresentaram os maiores valores de produto de energia (BHmáx = 145, 145 e 144 KJ.m-3, respectivamente). Já o ímã com adição de Mo apresentou o maior fator de quadratura (FQ = 0,73) entre todas as amostras, 28% superior ao ímã sem adição de elementos de liga. / Rare earth permanent magnets perform an important role in the electromagnetic devices industry, particularly in the production of hybrid and electric vehicle engines and generators for wind turbines. With the recent Chinese restriction on the export of rare-earth elements, the increasing prices and the need to replace the Dy in the permanent magnets, there is a worldwide interest in alternatives to these issues. The addition of alloying elements on rare-earth permanent magnets is one of the methods used to improve the magnetic properties. This present work evaluates the influence of Ti, V, Cr, Ni, Zr, Nb and Mo as alloying elements on the microstructure and magnetic properties of sintered Pr-Fe-Co-B based permanent magnets. The permanent magnets were produced by the conventional powder metallurgy route using powder obtained by hydrogen-decrepitation (HD) method. In order to produce the magnet Pr16Fe66,9Co10,7B5,7Cu0,7 without alloying elements the mixture of alloys method was employed, mixing two compositions: Pr20Fe73B5Cu2 (33% w.t) and Pr14Fe64Co16B6 (67% w.t). With the purpose of evaluating the influence of the alloying elements, the Pr14Fe64Co16B6M0,1 (where M= Ti, V, Cr, Ni Zr, Nb or Mo) (67% w.t) alloy was employed. The characterization of the alloys and the magnets was carried out using scanning electron microscopy (SEM), X-ray diffraction (XRD) and the magnetic properties were measured using a permeameter. The magnet with Cr addition (iHc = 836 KA.m-1) presented intrinsic coercivity 11,8% higher in comparsion with the magnet without any addition (iHc = 748 KA.m-1). The highest remanence was observed for the magnet with Nb addition (Br = 1.04 T). The magnets with additions of Ti, V and Zr produced the highest energy products (BHmáx = 145, 145 and 144 KJ.m3 respectively). The magnet with Mo addition showed the highest squareness factor (SF = 0.73) among of all samples, 28% higher than the magnet without addition.

Os ímãs permanentes de terras-raras tem um papel relevante na indústria de dispositivos eletromagnéticos, principalmente no que se refere à produção de motores para veículos híbridos e elétricos e geradores para turbinas eólicas. Com a recente restrição chinesa a exportação de terras-raras, os altos preços e a necessidade de substituição do Dy nesses ímãs, há um interesse mundial por alternativas a essas questões. A adição de elementos de liga em ímãs permanentes de terras raras tem como objetivo a melhora das propriedades magnéticas. O presente trabalho avalia a influência do Ti, V, Cr, Ni, Zr, Nb e Mo na microestrutura e nas propriedades magnéticas de ímãs sinterizados. Os ímãs foram preparados via metalurgia do pó, a partir de pós obtidos pelo processo de decrepitação por hidrogênio (HD). Na produção do ímã Pr16Fe66,9Co10,7B5,7Cu0,7, sem adição de elementos de liga, foi utilizada a mistura das ligas Pr20Fe73B5Cu2 (33% em peso) e Pr14Fe64Co16B6 (67% em peso). Para avaliar a influência das adições foi utilizada a liga Pr14Fe64Co16B6M0,1, onde M = Ti, V, Cr, Ni, Zr, Nb e Mo (67% em peso). As ligas utilizadas e os ímãs produzidos foram caracterizados por Microscopia Eletrônica de Varredura (MEV) e Difração de Raios-X (DRX), e as propriedades magnéticas foram obtidas por meio de Permeâmetro. O ímã com adição de Cr (iHc = 836 KA.m-1) apresentou coercividade intrínseca 11,8% superior ao ímã sem adição de elemento de liga (iHc = 748 KA.m-1). A maior remanência foi observada para o ímã com adição de Nb (Br = 1,04 T). Os ímãs com as adições de Ti, V e Zr apresentaram os maiores valores de produto de energia (BHmáx = 145, 145 e 144 KJ.m-3, respectivamente). Já o ímã com adição de Mo apresentou o maior fator de quadratura (FQ = 0,73) entre todas as amostras, 28% superior ao ímã sem adição de elementos de liga. / Rare earth permanent magnets perform an important role in the electromagnetic devices industry, particularly in the production of hybrid and electric vehicle engines and generators for wind turbines. With the recent Chinese restriction on the export of rare-earth elements, the increasing prices and the need to replace the Dy in the permanent magnets, there is a worldwide interest in alternatives to these issues. The addition of alloying elements on rare-earth permanent magnets is one of the methods used to improve the magnetic properties. This present work evaluates the influence of Ti, V, Cr, Ni, Zr, Nb and Mo as alloying elements on the microstructure and magnetic properties of sintered Pr-Fe-Co-B based permanent magnets. The permanent magnets were produced by the conventional powder metallurgy route using powder obtained by hydrogen-decrepitation (HD) method. In order to produce the magnet Pr16Fe66,9Co10,7B5,7Cu0,7 without alloying elements the mixture of alloys method was employed, mixing two compositions: Pr20Fe73B5Cu2 (33% w.t) and Pr14Fe64Co16B6 (67% w.t). With the purpose of evaluating the influence of the alloying elements, the Pr14Fe64Co16B6M0,1 (where M= Ti, V, Cr, Ni Zr, Nb or Mo) (67% w.t) alloy was employed. The characterization of the alloys and the magnets was carried out using scanning electron microscopy (SEM), X-ray diffraction (XRD) and the magnetic properties were measured using a permeameter. The magnet with Cr addition (iHc = 836 KA.m-1) presented intrinsic coercivity 11,8% higher in comparsion with the magnet without any addition (iHc = 748 KA.m-1). The highest remanence was observed for the magnet with Nb addition (Br = 1.04 T). The magnets with additions of Ti, V and Zr produced the highest energy products (BHmáx = 145, 145 and 144 KJ.m3 respectively). The magnet with Mo addition showed the highest squareness factor (SF = 0.73) among of all samples, 28% higher than the magnet without addition.

The main purpose of the thesis work is based on achieving same mechanical properties on the three different sized bearing housings. The key mechanical property that had to be focused on was the hardness of the parts. In order to achieve this goal, chemical compositions of the parts have studied. However there were some limitations on the composition variants. Allowed variables of the compositions are silicon, nickel and copper. Due to necessity another element, Molybdenum (Mo), was also introduced. After many simulations three different compositions are proposed. Then the feasibility of results of casting simulation software investigated. And finally an optimization guideline has proposed. Chemical composition researches have carried on casting simulation software, which is called Magma5. Following the completion of the simulations phase, proposed compositions trial casted at the company. Subsequent to trial castings cast parts had tested for their hardness values. In order to bring the thesis to completion simulation outputs and trial test results had compared. With the help of a casting simulation software composition optimisation of different sized parts could be easily optimised in order to achieve same results. Many simulations are executed with different composition for the silicon, nickel, copper and molybdenum variants. It was seen that Mo additions significantly increase the mechanical properties of the parts. Nickel and copperacts similarly on the hardness values, however nickel addition reduce undercooling tendency at a greater rate. Good inoculation is vital for the parts with thin sections. Decent inoculation helps to improve the microstructure and helps to get closer results tothe simulated values. However software represents key information aboutundercooled zones on the part. Software ensures 95% to 97% correct values on hardness results.

Les aciers bainitiques refroidis à l'air libre sont de plus en plus utilisés à la place des aciers martensitiques trempés et revenus pour la réalisation de pièces forgées dans le secteur automobile. Ces aciers permettent la réalisation d'économies significatives de temps et d'argent lors de leur fabrication. Leur résistance mécanique élevée est obtenue grâce à une composition chimique complexe, générant une microstructure multi-échelle et multiphasée lors du refroidissement à l'air libre. Dans un souci d'amélioration continue de cet acier, il devient nécessaire de comprendre plus en profondeur les mécanismes physiques mis en jeu lors de la décomposition de l'austénite. L'objectif principal de cette thèse est de contribuer à cette compréhension en établissant des liens quantitatifs entre la composition chimique, la microstructure et les propriétés mécaniques pour cette gamme d'aciers dans des conditions représentatives du forgeage. L'influence de plusieurs éléments d'alliage sur la microstructure brute de forge, ainsi que quelques synergies entre ces éléments, a été établie grâce à l'étude de diagrammes TRC spécifiques à l'application visée. Les mécanismes de rupture dominants et les paramètres microstructuraux contrôlant la résilience ont été identifiés par l'étude des faciès de rupture, de l'endommagement dans le volume et par des caractérisations microstructurales ciblées. Les contributions respectives de chaque mécanisme classique de durcissement structural ont été déterminées de manière quantitative, sur la base de plusieurs hypothèses et de paramètres microstructuraux. Au passage, des informations précieuses sur le comportement global en traction de ces aciers ont été récoltées grâces à l'étude des mécanismes d'endommagement et de rupture en traction.Tous ces résultats ont permis l'identification des paramètres microstructuraux, comme la taille de paquet bainitique et la fraction de constituants microstructuraux secondaires, qui doivent être pris en considération lors de l'optimisation de la composition chimique. / Air-cooled bainitic steel grades are increasingly being considered as substitutes to quenched & tempered martensitic steels in the realization of automotive forged parts. They allow significant manufacturing cost and time reductions. To compete with martensitic steels, high mechanical strength is provided by a complex chemical composition, leading to a multi-scale and multi-constituent microstructure after air-cooling. In order to optimize such chemical composition, need in rationalization of the steel grade development has emerged.The main aim of this Ph.D project was to build a physically based knowledge of the steel grade by making quantitative links between chemical composition, microstructure and mechanical properties in as-forged condition.The influence of several alloying elements on the as-forged microstructure, as well as some synergies, has been established using relevant CCT diagrams.Dominant fracture mechanisms and controlling microstructural parameters in concern of impact toughness have been identified with the help of comprehensive fracture surface, cross-section observations and targeted quantitative microstructural characterization.The respective contributions to yield strength of classical strengthening mechanisms have been quantitatively determined, based on several hypothesis and the use of several microstructural parameters. At the same, precious information on tensile behaviour has also been deduced from the observation of the fractured tensile test specimens.All these results allow identifying the key microstructural parameters, such as bainitic packet size or secondary microstructural constituents content, that have to be targeted in the alloy design.

<p>  </p> <p>Due to the difficulty in physically observing the phenomena inside the actual ladle furnace in the industry, to ascertain optimized methodology for high-grade steel production, an investigation was carried out using numerical modeling to simulate the behavior of alloying elements within the liquid steel bulk using ANSYS Fluent 2020 R1 (ANSYS Inc., Pittsburgh, PA, USA). The model solves the governing equations utilized in computing the trajectories of each particle in the discrete phase. Furthermore, a user defined (UDF) code maps the mass of each parcel based on the total amount of alloy injected. The code also defines the total time it takes for the shell formed around the added materials to melt or dissolve. The study consists of a two-step procedure: ladle stirring by argon inert gas injection and mixing study by injecting micro-alloying elements to capture the flow field, turbulence, and species transport occurring during the refining process. A generic dual plug ladle metallurgy furnace, dimensions, and data obtained from Nucor Steel is used to validate the CFD simulation results. Concise parametric studies consist of ladle geometry design adjustments, variations of argon gas flow rates, and different alloying elements. Though the efficiency of the LMF process is quantified using the mixing time, which decreases as initial gas flow rates increase, results from this study show that extremely high charging of ladles is optional in obtaining shorter mixing. Also, particles behave substantially differently when their densities are below or above that of steel, and their melting points and specific heat capacities influence the time it takes for them to melt or dissolve. The overall potential outcome for this study is to improve the mixing practices due to different optimal procedures required by some materials than others.</p>

Made available in DSpace on 2017-07-21T20:42:44Z (GMT). No. of bitstreams: 1 Adriano Murilo Rosario.pdf: 9074045 bytes, checksum: d9772c841442622e9ad77d48e4a5f6a2 (MD5) Previous issue date: 2012-10-22 / The present study aimed at analyzing the effects of alloying elements on the solidification curves of a gray cast iron using the thermal analysis technique. Inoculation was performed by adding of only 0.02% (in wt. %) of IM22 inoculant, in order to minimize undercooling and provide a minimal quantity of nucleation sites for graphite during solidification. A constant inoculation condition allows highlighting the influence of alloying elements in the cooling curves, as well as in the solidification parameters. The following elements have been added to the base metal (in wt. %): selenium (0.2% to 0.5%), nickel (0.2% to 0.5%), iron-phosphorus (0.2% to 1.0%), silicon (0.05% to 0.4%), lead (0.2% to 1.0%) and tin (0.2% to 0.8%). The elementary powders were characterized by scanning electron microscopy (SEM) with energy-dispersive X-ray microanalysis (EDX). The base metal was produced in a medium frequency induction furnace and its chemical composition corresponded to a FC-25 class. The samples obtained after the addition of alloying elements were characterized by optical microscopy, optical emission spectrometry, tensile and hardness tests. The results showed that selenium has a strong effect on undercooling, favoring the formation of eutectic carbides. Nickel tends to favor the formation of type "A” graphite. The phosphorus has the effect of reducing the tensile strength of gray iron and promotes the formation of steadite, consisting of the eutectic of ferrite and iron phosphide (Fe3P). The silicon favors the formation of type "A" graphite. Lead has deleterious effect on the morphology of graphite. Tin has the effect of increasing the mechanical properties. The use of thermal analysis technique allowed the finding of good correlations between the different solidification parameters studied. The stable and metastable eutectic temperatures are strongly affected by the alloying elements. Finally, new equations for the temperatures of stable and metastable eutectics are proposed. The equations are based on experimental results and data extracted from ATAS program. / O presente trabalho teve por objetivo principal analisar os efeitos dos elementos de liga nas curvas de solidificação de um ferro fundido cinzento, utilizando a técnica de análise térmica. A inoculação foi adicionada em um teor muito abaixo do utilizado na indústria metalúrgica, ou seja, de apenas 0,02% do inoculante IM22. O suficiente para haver número mínimo de substratos para a grafita nuclear durante a solidificação. A condição de inoculação constante teve por objetivo destacar a influência dos elementos de liga estudados nas curvas de resfriamento, bem como nos parâmetros de solidificação. Os seguintes elementos foram adicionados ao metal base: selênio (0,2 a 0,5% em peso), níquel (0,2 a 0,5% em peso), ferro-fósforo (0,2 a 1,0% em peso), silício (0,05 a 0,4% em peso), chumbo (0,2 a 1,0% em peso) e estanho (0,2 a 0,8% em peso). Os pós destes elementos foram caracterizados por microscopia eletrônica de varredura (MEV) com microanálise química por dispersão de raios x (EDS). O metal base foi fundido em um forno de indução de média frequência, sendo sua composição característica de um ferro fundido cinzento de classe FC-25, corrigindo-se apenas o carbono e o silício. As amostras obtidas após a adição dos elementos de liga foram caracterizadas por microscopia óptica, espectrometria de emissão óptica e ensaios mecânicos de tração e dureza. Os resultados mostram que o selênio possui um forte efeito no super-resfriamento, favorecendo a formação de carbetos eutéticos. O níquel tende ao favorecimento da formação da grafita do tipo “A”. O fósforo tem o efeito de diminuir a resistência à tração do ferro fundido cinzento e promove a formação de “esteadita”. O silício favorece a formação da grafita do tipo “A”. O chumbo tem efeito deletério na morfologia da grafita. O estanho tem o efeito de aumentar as propriedades mecânicas. A utilização da técnica de análise térmica permitiu encontrar uma boa correlação entre os diversos parâmetros de solidificação estudados. Os resultados mostram que os elementos de liga atuam fortemente nas temperaturas do eutético estável e do eutético metaestável. Por fim, são propostas novas equações para o cálculo das temperaturas dos eutéticos estável e metaestável. As equações são baseadas nos resultados experimentais e nos dados do programa ATAS.

One of the most important additives in High Speed Steels (HSS) is cobalt, mainly for its effect on the hot properties. Based on statistic data about the increased price of cobalt and its negative effect on human health, an ethical and financial barrier in the steel industry have occurred. In order to solve the problem, it is of great importance to examine the future cobalt price and accessibility, as well as examine the possibility of finding alternative substitutes to cobalt. The purpose of this project was therefore to examine alternatives to cobalt as an alloying element in HSS. A qualitative literature study was performed by analyzing the economy of cobalt, studying the main reasons for cobalts tendency to improve the hot properties of the steel and finding alternative elements to replace, or at least reduce, cobalt in HSS without degrading the hot properties. Cobalt is used both in the chemical and metallurgical business. But the demand of cobalt is largely driven by chemical purposes with the focus on its rechargeable battery applications. The analysis shows that there is nothing pointing at a significant decrease of the price of cobalt. Lithium ion batteries stands for about 50% of current cobalt supply, which is why the price has surged the recent years. The market for electric vehicles and rechargeable batteries has skyrocketed. To decrease the price of cobalt, a substitute for cobalt in rechargeable batteries would need to be found, which is not very likely for the time being. The effect of cobalt in HSS is mainly on the red hardness and tempering resistance. Cobalt increases the bonding strength in the steel matrix and changes the microstructure of the finer secondary carbides. Also the growth rate and coalescence rate of the carbides decreases. This causes the red hardness and the tempering resistance to increase. To replace cobalt, several alternative alloying elements have been researched. Among the most promising are niobium, nitrogen and aluminium, where niobium were found to be of most interest, due to the broad support of relevant articles in the field of powder metallurgical processing. The positive effect of niobium could be regarded as three-fold. The first contribution is the refinement of grain size and homogeneity of the primary carbides, which increases the overall hardness. The second effect is that the addition of niobium shifts the phase equilibria in such a way that the precipitation of primary carbides mainly will be in the form of hard and stable NbC. The majority of the other alloying elements will hence be precipitated as secondary carbides during tempering. The final effect is an increase in secondary hardness, as a consequence of the large amounts of vanadium and smaller amounts of niobium that is being precipitated during tempering to the secondary carbides. This enables a high matrix hardening potential in the optimal state of tempering.

Made available in DSpace on 2016-12-08T17:19:36Z (GMT). No. of bitstreams: 1 1 inicio-introducao.pdf: 82164 bytes, checksum: d209d70a553021390cbccad3fd2d33e9 (MD5) Previous issue date: 2010-07-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study evaluates the effect of chemical composition and heat treatment of aging on the mechanical properties of aluminum alloy 356. The variables of heat treatment were the magnesium content, time and temperature. Additionally, the effect of alloying elements present as Fe and Mn were also evaluated by comparing with the A356 which is the purest version of the 356.0 alloy. For alloy 356, two amount of magnesium were used, 0.3% and 0.5% in weight and the alloy was called the 356 low Mg and 356 high Mg, respectively.The samples were treated at constant temperature and varying times and after analysis of mechanical strength more specimens were cast that were treated at constant temperature, varying the time. In addition to tensile tests, other techniques were used to evaluate the material.Microhardness tests, optical microscopy and scanning electron microscopy analysis with point EDX were used.Comparing alloys with low and high magnesium content were observed significant variations in the mechanical properties .Besides this variable, the time and temperature of heat treatment also caused changes in the mechanical properties.At high temperatures can be observed the possible effect of over aging, where a decrease in mechanical strength was obsserved.In the microstructural analysis of the alloy 356 was noticed the presence of intermetallic iron-rich and the same was not found when we evaluated the microstructure of the alloy A356.As mechanical properties of A356 alloy showed values slightly lower than those obtained for the mechanical properties of alloys 356.This fact may be related to the presence of hardening elements such as copper and other alloying elements such as iron and manganese present in the alloy 356. / Este trabalho avalia o efeito da composição química e do tratamento térmico de envelhecimento sobre as propriedades mecânicas da liga de alumínio 356. As variáveis estudadas foram o teor de magnésio, o tempo e a temperatura de tratamento térmico. Adicionalmente, os efeitos de elementos de liga presentes como o Fe e o Mn também foram avaliados, através da comparação com a liga A356 que é a versão mais pura da liga 356.0. Para a liga 356, dois percentuais de magnésio foram utilizados, 0,3% e 0,5% em peso e a liga foi denominada 356 baixo Mg e 356 alto Mg respectivamente.Os corpos de prova foram tratados a temperatura constante e tempos variados e após análises de resistência mecânica foram fundidos mais corpos de prova que foram tratados a temperatura constante, variando o tempo.Além dos ensaios de tração, outras técnicas foram usadas para avaliar o material.Ensaios de microdureza, microscopia óptica e eletrônica de varredura com análises pontuais EDX foram utilizadas.Comparando as ligas com baixo e alto teor de magnésio foram observadas variações significativas nas propriedades mecânicas.Além desta variável, o tempo e a temperatura de tratamento térmico também causaram variações nas propriedades mecânicas.A altas temperaturas pode ser observado o possível efeito de superenvelhecimento, onde uma queda na resistência mecânica foi observada.Nas análises microestruturais da liga 356 pode se perceber a presença de intermetálicos ricos em ferro e o mesmo não foi encontrado quando foi avaliada a microestrutura da liga A356.As propriedades mecânicas da liga A356 apresentaram valores menores do que aqueles obtidos para as propriedades mecânicas das ligas 356.Este fato pode ser relacionado com a presença de elementos endurecedores como o cobre e outros elementos de liga como o ferro e o manganês presentes na liga 356.