{"title":"通过反应火花等离子烧结工艺加工的 Ti3SiC2-TiC 复合材料的动力学控制反应路径和微观结构发展","authors":"","doi":"10.1016/j.mtla.2024.102213","DOIUrl":null,"url":null,"abstract":"<div><p>Reactive spark plasma sintering of ternary Ti-Si-C system was performed using three different powder precursors systems 3Ti/Si/2C, 3Ti/SiC/C and 2Ti/TiC/Si, to explore the fundamental physics behind Ti<sub>3</sub>SiC<sub>2</sub> MAX phase formation, its stability and microstructure development, and, finally linked with its hardening and contact induced damage tolerance. Phase evolution in Ti-Si-C system is a complex phenomenon, and, present experimental conditions never yield a phase pure Ti<sub>3</sub>SiC<sub>2</sub> MAX phase, rather results in varying volume fractions of Ti<sub>3</sub>SiC<sub>2</sub>-(Ti<sub>x</sub>,Si<sub>1-x</sub>)C solid solution due to non-equilibrium processing conditions exerted by SPS processing which restricts coherent site specific diffusional jumps and promotes the formation of (Ti, Si)C solid-solution instead of well reported non-stoichiometric TiC<sub>x</sub>. 3Ti/SiC/C precursor was the best candidate for processing composite with highest yields of Ti<sub>3</sub>SiC<sub>2</sub>. Phase evolution is guided by the free energy of formation of different phases and chemical affinity amongst the constituent elements rather than the equilibrium phase diagram of the Ti-Si-C system. Presence of free carbon, low temperature liquid phase and slow heating rate are the key requirements for forming phase pure Ti<sub>3</sub>SiC<sub>2</sub>, where excess free carbon reduces the stability of Ti<sub>3</sub>SiC<sub>2</sub> via decarburization. Non-equilibrium processing conditions impart nano-precipitation of coherent hexagonal Ti<sub>3</sub>SiC<sub>2</sub> precipitates within a cubic (Ti, Si)C matrix with a distinct orientation relation of (220)<sub>matrix</sub> ║(0004)<sub>precipitate</sub> and <114><sub>matrix</sub> ║<2–1–10><sub>precipitate</sub> that has never been reported, instead of growing highest density plane of <em>hcp</em>-on-<em>fcc</em> matrix. Coherency strain and fine interlocking microstructure of the as-processed composite experiences ≈36 % of enhancement in hardness followed by an improved contact damage for the as-processed composite.</p></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":null,"pages":null},"PeriodicalIF":3.0000,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Kinetics-controlled reaction pathway and microstructure development of Ti3SiC2-TiC composite processed through reactive spark plasma sintering\",\"authors\":\"\",\"doi\":\"10.1016/j.mtla.2024.102213\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Reactive spark plasma sintering of ternary Ti-Si-C system was performed using three different powder precursors systems 3Ti/Si/2C, 3Ti/SiC/C and 2Ti/TiC/Si, to explore the fundamental physics behind Ti<sub>3</sub>SiC<sub>2</sub> MAX phase formation, its stability and microstructure development, and, finally linked with its hardening and contact induced damage tolerance. Phase evolution in Ti-Si-C system is a complex phenomenon, and, present experimental conditions never yield a phase pure Ti<sub>3</sub>SiC<sub>2</sub> MAX phase, rather results in varying volume fractions of Ti<sub>3</sub>SiC<sub>2</sub>-(Ti<sub>x</sub>,Si<sub>1-x</sub>)C solid solution due to non-equilibrium processing conditions exerted by SPS processing which restricts coherent site specific diffusional jumps and promotes the formation of (Ti, Si)C solid-solution instead of well reported non-stoichiometric TiC<sub>x</sub>. 3Ti/SiC/C precursor was the best candidate for processing composite with highest yields of Ti<sub>3</sub>SiC<sub>2</sub>. Phase evolution is guided by the free energy of formation of different phases and chemical affinity amongst the constituent elements rather than the equilibrium phase diagram of the Ti-Si-C system. Presence of free carbon, low temperature liquid phase and slow heating rate are the key requirements for forming phase pure Ti<sub>3</sub>SiC<sub>2</sub>, where excess free carbon reduces the stability of Ti<sub>3</sub>SiC<sub>2</sub> via decarburization. Non-equilibrium processing conditions impart nano-precipitation of coherent hexagonal Ti<sub>3</sub>SiC<sub>2</sub> precipitates within a cubic (Ti, Si)C matrix with a distinct orientation relation of (220)<sub>matrix</sub> ║(0004)<sub>precipitate</sub> and <114><sub>matrix</sub> ║<2–1–10><sub>precipitate</sub> that has never been reported, instead of growing highest density plane of <em>hcp</em>-on-<em>fcc</em> matrix. Coherency strain and fine interlocking microstructure of the as-processed composite experiences ≈36 % of enhancement in hardness followed by an improved contact damage for the as-processed composite.</p></div>\",\"PeriodicalId\":47623,\"journal\":{\"name\":\"Materialia\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":3.0000,\"publicationDate\":\"2024-09-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Materialia\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2589152924002102\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATERIALS SCIENCE, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Materialia","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2589152924002102","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
Kinetics-controlled reaction pathway and microstructure development of Ti3SiC2-TiC composite processed through reactive spark plasma sintering
Reactive spark plasma sintering of ternary Ti-Si-C system was performed using three different powder precursors systems 3Ti/Si/2C, 3Ti/SiC/C and 2Ti/TiC/Si, to explore the fundamental physics behind Ti3SiC2 MAX phase formation, its stability and microstructure development, and, finally linked with its hardening and contact induced damage tolerance. Phase evolution in Ti-Si-C system is a complex phenomenon, and, present experimental conditions never yield a phase pure Ti3SiC2 MAX phase, rather results in varying volume fractions of Ti3SiC2-(Tix,Si1-x)C solid solution due to non-equilibrium processing conditions exerted by SPS processing which restricts coherent site specific diffusional jumps and promotes the formation of (Ti, Si)C solid-solution instead of well reported non-stoichiometric TiCx. 3Ti/SiC/C precursor was the best candidate for processing composite with highest yields of Ti3SiC2. Phase evolution is guided by the free energy of formation of different phases and chemical affinity amongst the constituent elements rather than the equilibrium phase diagram of the Ti-Si-C system. Presence of free carbon, low temperature liquid phase and slow heating rate are the key requirements for forming phase pure Ti3SiC2, where excess free carbon reduces the stability of Ti3SiC2 via decarburization. Non-equilibrium processing conditions impart nano-precipitation of coherent hexagonal Ti3SiC2 precipitates within a cubic (Ti, Si)C matrix with a distinct orientation relation of (220)matrix ║(0004)precipitate and <114>matrix ║<2–1–10>precipitate that has never been reported, instead of growing highest density plane of hcp-on-fcc matrix. Coherency strain and fine interlocking microstructure of the as-processed composite experiences ≈36 % of enhancement in hardness followed by an improved contact damage for the as-processed composite.