Complex concentrated alloys (CCAs) offer the unique ability to tune composition and microstructure to achieve a wide range of mechanical performance. Recently, the development of metastable CCAs has led to the creation of transformation-induced plasticity (TRIP) CCAs. Similar to TRIP steels, TRIP CCAs are more effective at absorbing high strain rate loads when TRIP is activated during the loading process. The objective of our study is to investigate the effect of copper on the critical pressure for activating TRIP and the high pressure stability of a Fe(40-X)Mn20Cr15Co20Si5CuX TRIP CCA, where x varies from 0 to 3 at.% Cu. To achieve this goal, diamond anvil cell testing during in-situ synchrotron radiation X-ray diffraction was performed using both a monochromatic wide angle X-ray scattering (WAXS) beam and, for the first time ever, a polychromatic Laue diffraction beam on a CCA. Laue diffraction allows for real-time phase evolution tracking of the γ-fcc → ε-hcp transformation in a high pressure environment. Based on the results, a new method for processing and preparation of high pressure samples without changing the microstructure of sample was developed. This new method can be used to prepare any CCA samples for high pressure testing.

No description available.

O objeto da pesquisa foram as relações sociais estabelecidas entre o agente comunitário de saúde ACS e a equipe de Saúde da Família SF em situações concretas de trabalho. A SF é estratégia prioritária para a reorganização da Atenção Básica no Brasil. A profissão do ACS foi regulamentada somente em 2002 e caracteriza-se pelo exercício de atividades de prevenção de doenças e promoção da saúde. A literatura aponta que os ACS desempenham ações preconizadas pelo Ministério da Saúde, mas enfrentam dificuldades para cumprirem com funções de caráter mais político e social, voltadas para mudanças nos modos de se cuidar e para o aumento da participação social. O ACS possui características híbridas e singulares, pois é membro da comunidade e da equipe de saúde, propiciando a ligação entre esses dois atores. Objetivou-se compreender as relações sociais estabelecidas entre o ACS e a equipe de SF a partir do trabalho em equipe na saúde, destacando os aspectos da articulação das ações e da interação entre os trabalhadores. A pesquisa foi de abordagem qualitativa com a realização de 23 observações participantes e 11 entrevistas semi-estruturadas junto a uma equipe de SF em um município do interior paulista, O material empírico foi interpretado segundo a análise temática e compreendeu a história da unidade de saúde e seus trabalhadores, o processo de trabalho da equipe e os ACS na equipe de SF na perspectiva da articulação e da interação. Os resultados mostraram que o ACS está inserido em um processo de trabalho em equipe que é dinâmico. O ACS vive as contradições de modelos de saúde que são diferentes e co-existem em um mesmo espaço. Os ACS são laços de ligação quando desempenham ações articuladas ao trabalho da equipe e interagem com os trabalhadores, construindo planos assistenciais em comum. Um núcleo de competência do ACS pode ser a característica de laço de ligação, aproximando equipe e comunidade e adequando as ações de cuidado às reais necessidades das pessoas. Na prática comunicativa com os trabalhadores; os ACS ao falarem de si, estão falando da própria comunidade, pois é ele seu representante e porta-voz na equipe. Como elos de ligação desenvolvem ações essencialmente operacionais para agilizar o trabalho da equipe e da unidade, tais como, entregar recados e encaminhamentos. As atividades desempenhadas dentro da unidade relacionam-se à cooperação e também estão muito atreladas às ações operacionais e instrumentais do trabalho, inclusive com certo caráter de troca. Concluímos que a inserção do ACS na equipe de SF enfrenta dificuldades e requer a criação de estratégias que favoreçam a relação dialógica entre os trabalhadores. Assim, o trabalho da equipe e a dimensão política e social dos ACS poderão ser potencializados, contribuindo para cuidados mais integrais e acolhedores e para um agir em saúde mais criativo e prazeroso. / The social relations established between the community health agent (ACS) and the health family team (SF) in work situations was the object of this study. SF has been a strategic priority to reorganize Primary Health Care in Brazil. ACS only became a regulated profession in 2002 and comprises activities of disease prevention and health promotion. Literature appoints that ACS develops actions recommended by the Ministry of Health but faces difficulties in complying with functions with a more political and social character focused on changing peoples self-care and increasing their social participation. These professionals possess hybrid and singular characteristics because they are both members of the community and the health team making linkages between them. The study aimed to understand the social relations established between the ACS and SF team as from the work developed by the health team, highlighting connections between actions and interaction between workers. This is a qualitative study with 23 participant observations and 11 semistructured interviews with the SF team in a city in the interior of Sao Paulo, Brazil. The empirical material was analyzed according to the thematic analysis and comprises the history of the health unit and its workers, the teamwork process and the perspective of connection and interaction of the ACS in the SF team. Results revealed that ACS is inserted in a dynamic teamwork process, that is, experiences the contradictions of co-existing different health models. These professionals work as links when they develop actions connected to the teamwork and interact with its workers developing common care plans. The ACS core of competency is characterized by the connection they establish approximating team and community and adapting care actions to peoples real needs. When these professionals talk about themselves during communication with workers, they talk about the community itself because they are its representatives and spokesman in the team. As links, they basically develop operational actions to speed up the team and units work such as delivering messages and referrals. The activities developed inside the unit are related to cooperation and are also very associated to operational and instrumental work, which includes a certain exchange. The conclusion is that the inclusion of the ACS in the SF team is difficult and requires strategies favoring the dialogical relation between workers. This way, the teamwork and the ACS political and social dimensions can be strengthened, contributing to more integral and welcoming care and also to more creative and gratifying work in health.

O objeto da pesquisa foram as relações sociais estabelecidas entre o agente comunitário de saúde ACS e a equipe de Saúde da Família SF em situações concretas de trabalho. A SF é estratégia prioritária para a reorganização da Atenção Básica no Brasil. A profissão do ACS foi regulamentada somente em 2002 e caracteriza-se pelo exercício de atividades de prevenção de doenças e promoção da saúde. A literatura aponta que os ACS desempenham ações preconizadas pelo Ministério da Saúde, mas enfrentam dificuldades para cumprirem com funções de caráter mais político e social, voltadas para mudanças nos modos de se cuidar e para o aumento da participação social. O ACS possui características híbridas e singulares, pois é membro da comunidade e da equipe de saúde, propiciando a ligação entre esses dois atores. Objetivou-se compreender as relações sociais estabelecidas entre o ACS e a equipe de SF a partir do trabalho em equipe na saúde, destacando os aspectos da articulação das ações e da interação entre os trabalhadores. A pesquisa foi de abordagem qualitativa com a realização de 23 observações participantes e 11 entrevistas semi-estruturadas junto a uma equipe de SF em um município do interior paulista, O material empírico foi interpretado segundo a análise temática e compreendeu a história da unidade de saúde e seus trabalhadores, o processo de trabalho da equipe e os ACS na equipe de SF na perspectiva da articulação e da interação. Os resultados mostraram que o ACS está inserido em um processo de trabalho em equipe que é dinâmico. O ACS vive as contradições de modelos de saúde que são diferentes e co-existem em um mesmo espaço. Os ACS são laços de ligação quando desempenham ações articuladas ao trabalho da equipe e interagem com os trabalhadores, construindo planos assistenciais em comum. Um núcleo de competência do ACS pode ser a característica de laço de ligação, aproximando equipe e comunidade e adequando as ações de cuidado às reais necessidades das pessoas. Na prática comunicativa com os trabalhadores; os ACS ao falarem de si, estão falando da própria comunidade, pois é ele seu representante e porta-voz na equipe. Como elos de ligação desenvolvem ações essencialmente operacionais para agilizar o trabalho da equipe e da unidade, tais como, entregar recados e encaminhamentos. As atividades desempenhadas dentro da unidade relacionam-se à cooperação e também estão muito atreladas às ações operacionais e instrumentais do trabalho, inclusive com certo caráter de troca. Concluímos que a inserção do ACS na equipe de SF enfrenta dificuldades e requer a criação de estratégias que favoreçam a relação dialógica entre os trabalhadores. Assim, o trabalho da equipe e a dimensão política e social dos ACS poderão ser potencializados, contribuindo para cuidados mais integrais e acolhedores e para um agir em saúde mais criativo e prazeroso. / The social relations established between the community health agent (ACS) and the health family team (SF) in work situations was the object of this study. SF has been a strategic priority to reorganize Primary Health Care in Brazil. ACS only became a regulated profession in 2002 and comprises activities of disease prevention and health promotion. Literature appoints that ACS develops actions recommended by the Ministry of Health but faces difficulties in complying with functions with a more political and social character focused on changing peoples self-care and increasing their social participation. These professionals possess hybrid and singular characteristics because they are both members of the community and the health team making linkages between them. The study aimed to understand the social relations established between the ACS and SF team as from the work developed by the health team, highlighting connections between actions and interaction between workers. This is a qualitative study with 23 participant observations and 11 semistructured interviews with the SF team in a city in the interior of Sao Paulo, Brazil. The empirical material was analyzed according to the thematic analysis and comprises the history of the health unit and its workers, the teamwork process and the perspective of connection and interaction of the ACS in the SF team. Results revealed that ACS is inserted in a dynamic teamwork process, that is, experiences the contradictions of co-existing different health models. These professionals work as links when they develop actions connected to the teamwork and interact with its workers developing common care plans. The ACS core of competency is characterized by the connection they establish approximating team and community and adapting care actions to peoples real needs. When these professionals talk about themselves during communication with workers, they talk about the community itself because they are its representatives and spokesman in the team. As links, they basically develop operational actions to speed up the team and units work such as delivering messages and referrals. The activities developed inside the unit are related to cooperation and are also very associated to operational and instrumental work, which includes a certain exchange. The conclusion is that the inclusion of the ACS in the SF team is difficult and requires strategies favoring the dialogical relation between workers. This way, the teamwork and the ACS political and social dimensions can be strengthened, contributing to more integral and welcoming care and also to more creative and gratifying work in health.

The novel alloying concept of high-entropy alloys (HEAs) has been the focus of many recent investigations revealing an interesting combination of properties. Alloying with aluminium and titanium showed strong influence on microstructure and phase composition. However, detailed investigations on the influence of titanium are lacking. In this study, the influence of titanium in the alloy system AlCoCrFeNiTix was studied in a wide range (molar ratios x = 0.0; 0.2; 0.5; 0.8; 1.0; 1.5). Detailed studies investigating the microstructure, chemical composition, phase composition, solidification behaviour, and wear behaviour were carried out. Alloying with titanium showed strong influence on the resulting microstructure and lead to an increase of microstructural heterogeneity. Phase analyses revealed the formation of one body-centred cubic (bcc) phase for the alloy without titanium, whereas alloying with titanium caused the formation of two different bcc phases as main phases. Additional phases were detected for alloys with increased titanium content. For x ≥ 0.5, a minor phase with face-centred cubic (fcc) structure was formed. Further addition of titanium led to the formation of complex phases. Investigation of wear behaviour revealed a superior wear resistance of the alloy AlCoCrFeNiTi0.5 as compared to a bearing steel sample.

No description available.

The investigation of high-entropy alloys (HEAs) has revealed many promising properties. HEAs with a high share of Al and Ti are suitable for the formation of lightweight materials. Investigations of the alloy system AlCoCrFeNiTi showed high strength, hardness, ductility, and wear resistance, which makes this special alloy interesting for surface engineering and particularly for thermal spray technology. In this study, the suitability of inert gas-atomised HEA powder for high-velocity-oxygen-fuel (HVOF) thermal spray is investigated. This process allows for high particle velocities and comparatively low process temperatures, resulting in dense coatings with a low oxidation. The microstructure and phase composition of the atomised powder and the HVOF coating were investigated, as well as the wear behaviour under various conditions. A multiphase microstructure was revealed for the powder and coating, whereas a chemically ordered bcc phase occurred as the main phase. The thermal spray process resulted in a slightly changed lattice parameter of the main phase and an additional phase. In comparison with a hard chrome-plated sample, an increase in wear resistance was achieved. Furthermore, no brittle behaviour occurred under abrasive load in the scratch test. The investigation of wear tracks showed only minor cracking and spallation under maximum load.

The investigation of high-entropy alloys (HEAs) has revealed many promising properties. HEAs with a high share of Al and Ti are suitable for the formation of lightweight materials. Investigations of the alloy system AlCoCrFeNiTi showed high strength, hardness, ductility, and wear resistance, which makes this special alloy interesting for surface engineering and particularly for thermal spray technology. In this study, the suitability of inert gas-atomised HEA powder for high-velocity-oxygen-fuel (HVOF) thermal spray is investigated. This process allows for high particle velocities and comparatively low process temperatures, resulting in dense coatings with a low oxidation. The microstructure and phase composition of the atomised powder and the HVOF coating were investigated, as well as the wear behaviour under various conditions. A multiphase microstructure was revealed for the powder and coating, whereas a chemically ordered bcc phase occurred as the main phase. The thermal spray process resulted in a slightly changed lattice parameter of the main phase and an additional phase. In comparison with a hard chrome-plated sample, an increase in wear resistance was achieved. Furthermore, no brittle behaviour occurred under abrasive load in the scratch test. The investigation of wear tracks showed only minor cracking and spallation under maximum load.

In this study, the wear behaviour of a powder metallurgically produced AlCoCrFeNiTi0.5 high-entropy alloy (HEAs) is investigated at elevated temperatures. Spark plasma sintering (SPS) of inert gas atomised feedstock enables the production of dense bulk material. The microstructure evolution and phase formation are analysed. The high cooling rate in the atomisation process results in spherical powder with a microstructure comprising two finely distributed body-centred cubic phases. An additional phase with a complex crystal structure precipitates during SPS processing, while no coarsening of microstructural features occurs. The wear resistance under reciprocating wear conditions increases at elevated temperatures due to the formation of a protective oxide layer under atmospherical conditions. Additionally, the coefficient of friction (COF) slightly decreases with increasing temperature. SPS processing is suitable for the production of HEA bulk material. An increase in the wear resistance at elevated temperature enables high temperature applications of the HEA system AlCoCrFeNiTi0.5.

High hardness and good wear resistance have been revealed for the high-entropy alloy (HEA) system AlCoCrFeNiTi, confirming the potential for surface protection applications. Detailed studies to investigate the microstructure and phase formation have been carried out using different production routes. Powder metallurgical technologies allow for much higher flexibility in the customisation of materials compared to casting processes. Particularly, spark plasma sintering (SPS) enables the fast processing of the feedstock, the suppression of grain coarsening and the production of samples with a low porosity. Furthermore, solid lubricants can be incorporated for the improvement of wear resistance and the reduction of the coefficient of friction (COF). This study focuses on the production of AlCoCrFeNiTi composites comprising solid lubricants. Bulk materials with a MoS2 content of up to 15 wt % were produced. The wear resistance and COF were investigated in detail under sliding wear conditions in ball-on-disk tests at room temperature and elevated temperature. At least 10 wt % of MoS2 was required to improve the wear behaviour in both test conditions. Furthermore, the effects of the production route and the content of solid lubricant on microstructure formation and phase composition were investigated. Two major body-centred cubic (bcc) phases were detected in accordance with the feedstock. The formation of additional phases indicated the decomposition of MoS2.