A new class of materials, known as multi-functional energetic structural materials (MESMs), has been developed. These materials possess both strength and energetic functionalities, serving as candidates for many exciting applications. One of such applications is ballistic missiles, where these materials serve as part of structural casing as well as explosive payload. In this study, the dynamic compressive behavior of two types of MESMs in the intermediate strain rate regime is investigated. The first type is a thermite mixture of Al and Fe₂O₃ particles suspended in an epoxy matrix. The second type is a shock compacted mixture of Ni and Al powders. Compression experiments on a split-Hopkinson pressure bar (SHPB) apparatus are carried out at strain rates on the order of 103 s-1. In addition, a novel method for investigating the dynamic hardness of the Al + Fe₂O₃ + Epoxy materials is developed. In this method, high-speed digital photography is used to obtain time-resolved measurements of the indentation diameter throughout the indentation process. Experiments show that the shock compacted Ni-Al material exhibits a rather ductile behavior and the deformation of the Al + Fe₂O₃ + Epoxy mixtures is dominated by the polymer phase and significantly modulated by the powder phases. The pure epoxy is ductile with elastic-plastic hardening, softening, and perfectly plastic stages of deformation. The Al and Fe₂O₃ particles in Al + Fe₂O₃ + Epoxy mixtures act as reinforcements for the polymer matrix, impeding the deformation of the polymer chains, alleviating the strain softening of the glassy polymer matrix at lower levels of powder contents (21.6 - 29.2% by volume), and imparting the attributes of strain hardening to the mixtures at higher levels of powder contents (21.6 - 49.1% by volume). Both the dynamic and quasi-static hardness values of the Al + Fe₂O₃ + Epoxy mixtures increase with powder content, consistent with the trend seen in the stress-strain curves. To quantify the constitutive behavior of the 100% epoxy and the Al + Fe₂O₃ + Epoxy materials, the experimentally obtained stress-strain curves are fitted to the Hasan-Boyce model. This model uses a distribution of activation energies to characterize the energy barrier for the initiation of localized shear transformations of long chain polymeric molecules. The results show that an increase in powder content increases the activation energy, decreases the number of transformation sites, causes redistribution of applied strain energy, and enhances the storage of inelastic work. These effects lead to enhanced strength and strain hardening rate at higher levels of powder content.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 160-167). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 160-167). Also available on the Internet.

A moldagem de pós por injeção (MPI) foi empregada neste trabalho para a fabricação de micro componentes de uma pinça de biópsia, através do desenvolvimento de misturas injetáveis. Utilizou-se a liga de aço inoxidável AISI 316L, liga reconhecidamente biocompatível, para obtenção dos micro componentes. Determinando a quantidade de 39% em volume para fração orgânica das quatro formulações de misturas injetáveis produzidas neste trabalho. Os polímeros estruturais empregados foram o PP, o PEBDL, o PEAD e o PMMA. Como material auxiliar de fluxo foi utilizada a parafina e para agente surfactante, o ácido esteárico. O desenvolvimento do sistema de extração química do polímero auxiliar de fluxo com solvente e posterior extração térmica do ligante em forno convencional e em um reator a plasma foram testados, ainda se empregou estes para testes em sinterização a temperaturas 1200°C, 1250°C e 1300°C. A extração química foi realizada com hexano atingindo 2,41% em massa de material extraído das amostras, após seis horas em um sistema aquecido entre 60°C e 70°C e uma atmosfera de vácuo. As amostras foram testadas química, física, mecânica e eletroquimicamente. Obteve-se os melhores resultados em termos de densificação de 7,05 g/cm³ para as amostras extraídas a plasma e sinterizadas a 1300 °C à vácuo em forno tubular. Isso significa uma densificação de 88,96% comparada a densidade do material comercial cuja a densidade é 7,93 g/cm³. As microdurezas encontradas nas amostras sinterizadas a 1300 °C em um forno convencional obtiveram valores de 208HV se mostrando maiores do que os 165HV obtido de um material maciço fabricado pelo extrusão e comercialmente vendido. Encontrou-se a dureza de 55HRB nas amostras processadas a 1300 °C, devido a presença de poros em componentes sinterizados. Nos componentes maciços foram medidos a dureza de 88HRB que foi maior que os resultados das amostras sinterizadas. As análises metalográficas mostraram um tamanho de grão variando entre, 30 e 50μm, se comparado ao tamanho de partícula médio do D90 de foi de 8,59 μm, se estima que este aumento foi entorno de três vezes e meia. Os testes químicos revelaram que a extração térmica em reatores a plasma melhoram significativamente os níveis de C, N, H e S quando comparados ao processo de extração térmica em forno convencional. A redução dos níveis de carbono residual, resultaram em diminuição do carboneto de cromo nas amostras, provocando uma menor corrosão. As amostras sinterizadas a 1200 °C a plasma apresentaram os melhores resultados de corrosão. / The powders injection molding (PIM) was used in this research, with objective to manufacture micro component, for application in biopsy forceps being developed injectable mixtures . It was used the powder stainless steel AISI 316L alloy, material biocompatible, to obtain the micro components. Through tests was determining the amount optimal volume in 39 % for the organic fraction of the four formulations of injectable mixtures produced in this research. The structural polymers used were PP , LLDPE , HDPE and PMMA . The paraffin was used as auxiliary material flow, the surfactant agent employed that was stearic acid . The development of chemical debiding and the thermal extraction for binder system, was used the conventional furnace and in a plasma reactor were tested also be employed for these tests sintering temperature 1200 ° C , 1250 °C and 1300 °C. Chemical extraction was performed with hexane achieving 2.41 % by extracted mass of sample material, after six hours in a heated system between 60 °C and 70 °C and a vacuum atmosphere. The samples were tested analysis by chemical , physical , mechanical and electrochemical.If it obtained the best results in terms of densification of 7.05g/cm ³ for plasma samples extracted and sintering at 1300 °C in vacuum tube furnace . This means densification of 88.96 % compared to the density of commercial material whose density is 7.93 g/cm ³ . The microhardness found in the samples sintered at 1300°C in a conventional furnace obtained 208HV microhardness showing larger than the commercial 165HV. Found that the HRB hardness of 55 in the samples processed at 1300 °C, due to the presence of pores in sintered parts. In the extruded components were measured hardness of 88HRB which was higher than the results of the sintered samples. The metallographic analysis showing a grain size ranging between 30 and 50μm , compared to the average particle size D90 was 8,59 microns is estimated that this increase was around three and half times . The chemical tests revealed that the thermal plasma extraction reactor significantly improve the levels of C, N , H and S compared to the process heat extraction in a conventional furnace . The residual carbon levels significantly improved, which helps to avoid the formation of chromium carbides , which aumnetou corrosion resistance . The best results in terms of corrosion were found for the samples sintered at 1200 ° C the plasma.

A moldagem de pós por injeção (MPI) foi empregada neste trabalho para a fabricação de micro componentes de uma pinça de biópsia, através do desenvolvimento de misturas injetáveis. Utilizou-se a liga de aço inoxidável AISI 316L, liga reconhecidamente biocompatível, para obtenção dos micro componentes. Determinando a quantidade de 39% em volume para fração orgânica das quatro formulações de misturas injetáveis produzidas neste trabalho. Os polímeros estruturais empregados foram o PP, o PEBDL, o PEAD e o PMMA. Como material auxiliar de fluxo foi utilizada a parafina e para agente surfactante, o ácido esteárico. O desenvolvimento do sistema de extração química do polímero auxiliar de fluxo com solvente e posterior extração térmica do ligante em forno convencional e em um reator a plasma foram testados, ainda se empregou estes para testes em sinterização a temperaturas 1200°C, 1250°C e 1300°C. A extração química foi realizada com hexano atingindo 2,41% em massa de material extraído das amostras, após seis horas em um sistema aquecido entre 60°C e 70°C e uma atmosfera de vácuo. As amostras foram testadas química, física, mecânica e eletroquimicamente. Obteve-se os melhores resultados em termos de densificação de 7,05 g/cm³ para as amostras extraídas a plasma e sinterizadas a 1300 °C à vácuo em forno tubular. Isso significa uma densificação de 88,96% comparada a densidade do material comercial cuja a densidade é 7,93 g/cm³. As microdurezas encontradas nas amostras sinterizadas a 1300 °C em um forno convencional obtiveram valores de 208HV se mostrando maiores do que os 165HV obtido de um material maciço fabricado pelo extrusão e comercialmente vendido. Encontrou-se a dureza de 55HRB nas amostras processadas a 1300 °C, devido a presença de poros em componentes sinterizados. Nos componentes maciços foram medidos a dureza de 88HRB que foi maior que os resultados das amostras sinterizadas. As análises metalográficas mostraram um tamanho de grão variando entre, 30 e 50μm, se comparado ao tamanho de partícula médio do D90 de foi de 8,59 μm, se estima que este aumento foi entorno de três vezes e meia. Os testes químicos revelaram que a extração térmica em reatores a plasma melhoram significativamente os níveis de C, N, H e S quando comparados ao processo de extração térmica em forno convencional. A redução dos níveis de carbono residual, resultaram em diminuição do carboneto de cromo nas amostras, provocando uma menor corrosão. As amostras sinterizadas a 1200 °C a plasma apresentaram os melhores resultados de corrosão. / The powders injection molding (PIM) was used in this research, with objective to manufacture micro component, for application in biopsy forceps being developed injectable mixtures . It was used the powder stainless steel AISI 316L alloy, material biocompatible, to obtain the micro components. Through tests was determining the amount optimal volume in 39 % for the organic fraction of the four formulations of injectable mixtures produced in this research. The structural polymers used were PP , LLDPE , HDPE and PMMA . The paraffin was used as auxiliary material flow, the surfactant agent employed that was stearic acid . The development of chemical debiding and the thermal extraction for binder system, was used the conventional furnace and in a plasma reactor were tested also be employed for these tests sintering temperature 1200 ° C , 1250 °C and 1300 °C. Chemical extraction was performed with hexane achieving 2.41 % by extracted mass of sample material, after six hours in a heated system between 60 °C and 70 °C and a vacuum atmosphere. The samples were tested analysis by chemical , physical , mechanical and electrochemical.If it obtained the best results in terms of densification of 7.05g/cm ³ for plasma samples extracted and sintering at 1300 °C in vacuum tube furnace . This means densification of 88.96 % compared to the density of commercial material whose density is 7.93 g/cm ³ . The microhardness found in the samples sintered at 1300°C in a conventional furnace obtained 208HV microhardness showing larger than the commercial 165HV. Found that the HRB hardness of 55 in the samples processed at 1300 °C, due to the presence of pores in sintered parts. In the extruded components were measured hardness of 88HRB which was higher than the results of the sintered samples. The metallographic analysis showing a grain size ranging between 30 and 50μm , compared to the average particle size D90 was 8,59 microns is estimated that this increase was around three and half times . The chemical tests revealed that the thermal plasma extraction reactor significantly improve the levels of C, N , H and S compared to the process heat extraction in a conventional furnace . The residual carbon levels significantly improved, which helps to avoid the formation of chromium carbides , which aumnetou corrosion resistance . The best results in terms of corrosion were found for the samples sintered at 1200 ° C the plasma.

A moldagem de pós por injeção (MPI) foi empregada neste trabalho para a fabricação de micro componentes de uma pinça de biópsia, através do desenvolvimento de misturas injetáveis. Utilizou-se a liga de aço inoxidável AISI 316L, liga reconhecidamente biocompatível, para obtenção dos micro componentes. Determinando a quantidade de 39% em volume para fração orgânica das quatro formulações de misturas injetáveis produzidas neste trabalho. Os polímeros estruturais empregados foram o PP, o PEBDL, o PEAD e o PMMA. Como material auxiliar de fluxo foi utilizada a parafina e para agente surfactante, o ácido esteárico. O desenvolvimento do sistema de extração química do polímero auxiliar de fluxo com solvente e posterior extração térmica do ligante em forno convencional e em um reator a plasma foram testados, ainda se empregou estes para testes em sinterização a temperaturas 1200°C, 1250°C e 1300°C. A extração química foi realizada com hexano atingindo 2,41% em massa de material extraído das amostras, após seis horas em um sistema aquecido entre 60°C e 70°C e uma atmosfera de vácuo. As amostras foram testadas química, física, mecânica e eletroquimicamente. Obteve-se os melhores resultados em termos de densificação de 7,05 g/cm³ para as amostras extraídas a plasma e sinterizadas a 1300 °C à vácuo em forno tubular. Isso significa uma densificação de 88,96% comparada a densidade do material comercial cuja a densidade é 7,93 g/cm³. As microdurezas encontradas nas amostras sinterizadas a 1300 °C em um forno convencional obtiveram valores de 208HV se mostrando maiores do que os 165HV obtido de um material maciço fabricado pelo extrusão e comercialmente vendido. Encontrou-se a dureza de 55HRB nas amostras processadas a 1300 °C, devido a presença de poros em componentes sinterizados. Nos componentes maciços foram medidos a dureza de 88HRB que foi maior que os resultados das amostras sinterizadas. As análises metalográficas mostraram um tamanho de grão variando entre, 30 e 50μm, se comparado ao tamanho de partícula médio do D90 de foi de 8,59 μm, se estima que este aumento foi entorno de três vezes e meia. Os testes químicos revelaram que a extração térmica em reatores a plasma melhoram significativamente os níveis de C, N, H e S quando comparados ao processo de extração térmica em forno convencional. A redução dos níveis de carbono residual, resultaram em diminuição do carboneto de cromo nas amostras, provocando uma menor corrosão. As amostras sinterizadas a 1200 °C a plasma apresentaram os melhores resultados de corrosão. / The powders injection molding (PIM) was used in this research, with objective to manufacture micro component, for application in biopsy forceps being developed injectable mixtures . It was used the powder stainless steel AISI 316L alloy, material biocompatible, to obtain the micro components. Through tests was determining the amount optimal volume in 39 % for the organic fraction of the four formulations of injectable mixtures produced in this research. The structural polymers used were PP , LLDPE , HDPE and PMMA . The paraffin was used as auxiliary material flow, the surfactant agent employed that was stearic acid . The development of chemical debiding and the thermal extraction for binder system, was used the conventional furnace and in a plasma reactor were tested also be employed for these tests sintering temperature 1200 ° C , 1250 °C and 1300 °C. Chemical extraction was performed with hexane achieving 2.41 % by extracted mass of sample material, after six hours in a heated system between 60 °C and 70 °C and a vacuum atmosphere. The samples were tested analysis by chemical , physical , mechanical and electrochemical.If it obtained the best results in terms of densification of 7.05g/cm ³ for plasma samples extracted and sintering at 1300 °C in vacuum tube furnace . This means densification of 88.96 % compared to the density of commercial material whose density is 7.93 g/cm ³ . The microhardness found in the samples sintered at 1300°C in a conventional furnace obtained 208HV microhardness showing larger than the commercial 165HV. Found that the HRB hardness of 55 in the samples processed at 1300 °C, due to the presence of pores in sintered parts. In the extruded components were measured hardness of 88HRB which was higher than the results of the sintered samples. The metallographic analysis showing a grain size ranging between 30 and 50μm , compared to the average particle size D90 was 8,59 microns is estimated that this increase was around three and half times . The chemical tests revealed that the thermal plasma extraction reactor significantly improve the levels of C, N , H and S compared to the process heat extraction in a conventional furnace . The residual carbon levels significantly improved, which helps to avoid the formation of chromium carbides , which aumnetou corrosion resistance . The best results in terms of corrosion were found for the samples sintered at 1200 ° C the plasma.

The pores in pressed and sintered components constitute weak points in the material since the stress concentration is larger than the nominal stress there. Therefore, fatigue cracks initiate at the pores. Specifically, it can be assumed that the fatigue cracks initiate at the largest pore in the stressed volume. Studies have previously looked at finding ways to model the fatigue strength of the material based on the largest pore. This thesis looks at a model previously derived for hardened pressed and sintered materials that is based on linear elastic fracture mechanics and investigates if said model can be modified to include non-hardened pressed and sintered materials that do not necessarily behave linear elastically. A model describing the influence of the size of the largest pore on the fatigue limit using empirical coefficients is suggested. Furthermore, the area of the largest pore is modelled using extreme value statistics. The model proved successful in modelling the density effect of the porosity on the fatigue strength for two materials with different microstructures: one with a homogeneous microstructure and one with a heterogeneous microstructure. For the material with the homogenoeous microstructure the model also accounted well for the notch effect when tested on samples with a different geometry. However, for the heterogeneous material the model did not account for the notch effect. Deformation hardening due to local plastic deformation in the softer phases was suggested as a possible explanation and was supported by tensile tests.

This qualification work consist of 123 pages, 30 pictures, 13 tables, 61 references and 2 appendixes. Object – Additive manufacturing in metallurgy. Subject – Organizational, technical and economic relations arising in the manufacturing processes of products based on additive technologies. The main purpose is developing of recommendations for involving the additive technologies taken into account business processes’ changes and production activities’ reflections of economic models. Research objectives: 1 Studying the influence of additive technologies on economic development in Russia and abroad. Identifying the main application branches of manufacturing. 2 Determination the current trends in additive technologies’ progress. Characterization the main processes and specifications. 3 Creating strategic elements for implementing the additive technologies, making aspects of business processes and functional economic models. Scientific novelty lies in the forming the upgraded supply chain at the areas of internal and external environment, and working-out universal business model of companies’ activities in the case of involving the additive technologies. Investment projects were calculating for comparison between the SLM and EBM technologies. Indicators of investment attractiveness of these technologies are presented. A method has been developed that allows to assess the ability of companies to introduce additive technologies, which has an advisory nature. / Выпускная квалификационная работа магистранта содержит 123 с, 30 рис., 13 табл., 61 библиографический источник, 2 приложения. Объект исследования – аддитивные технологии в металлургии. Предмет исследования – организационно-технические и экономические отношения, возникающие в процессе изготовления изделий на основе аддитивных технологий. Целью диссертационной работы является разработка рекомендаций по внедрению аддитивных технологий в металлургическое производство с учетом изменений в бизнес-процессах и экономических моделях, отражающих производственную деятельность предприятий. Цель обусловила ряд следующих задач: 1 Изучить влияние аддитивных технологий на экономическое развитие в России и за рубежом, обозначить основные перспективы их применения в различных отраслях экономики. 2 Определить современные тенденции развития аддитивных технологий в металлургии, охарактеризовать основные технологические процессы и их параметры. 3 Разработать элементы стратегии внедрения аддитивных технологий с учетом изменения в бизнес-процессах и экономических моделях функционирования организаций. Дано описание процессов аддитивного производства. За основу были взяты наиболее изученные технологии – процессы SLM и EBM, применительно к производству изделий из сплава Ti-6Al-4V и его отечественного аналога, сплава ВТ6. Приведены аспекты влияния аддитивных технологий на изменения в цепочках поставок и бизнес-моделях функционирования организации. Произведены расчеты инвестиционных проектов представленных технологий аддитивного производства. Представлен механизм оценки возможности организации к внедрению аддитивных технологий, имеющий рекомендательный характер.