The chemical stability,electronic structures,mechanical properties and Debye temperature of Fe-MnAl alloys were investigated using first-principles calculations.The formation enthalpy and cohesive energy are negative ...The chemical stability,electronic structures,mechanical properties and Debye temperature of Fe-MnAl alloys were investigated using first-principles calculations.The formation enthalpy and cohesive energy are negative for Fe-Mn-Al alloys,showing that they are thermodynamically stable.FeAl has the lowest formation enthalpy,indicating that FeAl is the most stable alloy in the Fe-Mn-Al system.The partial density of states,total density of states and electron density distribution maps were used to analyze the physical properties of the Fe-MnAl alloys.A combination of mainly covalent and metallic bonds exists in these Fe-Mn-Al alloys,resulting in good electronic conductivity,high melting points,and high hardness.These alloys display disparate anisotropy due to the calculated different shapes of the 3D curved surface of the Young's modulus and anisotropic index.FeAl has the highest bulk modulus,shear modulus and Yong's modulus of 187.1,119.8 and 296.2 GPa,respectively.Further,the Debye temperatures and sound velocity of these Fe-Mn-Al compounds were explored.展开更多
Phase equilibria at Fe-Mn side of isothermal section at 1000 and 1100℃ in Fe-Mn- Al system have been determined using the diffusion couple technique and metallography. A three-phase,α+γ+β,region was found at 1000...Phase equilibria at Fe-Mn side of isothermal section at 1000 and 1100℃ in Fe-Mn- Al system have been determined using the diffusion couple technique and metallography. A three-phase,α+γ+β,region was found at 1000℃.The method of solid/gas diffusion couple used to determine equilibrium phase composition is believed to be feasible for the system containing volatile component.展开更多
汽车行业的迅速发展使得能源消耗、环境污染等问题日益严重,而开发高强度且轻量化的汽车用钢对节能减排具有重要意义。目前正在研发的第三代先进高强钢包括轻质(Lightweight)钢、Q&P(Quenching and partitioning)钢和中锰钢(Mn质量...汽车行业的迅速发展使得能源消耗、环境污染等问题日益严重,而开发高强度且轻量化的汽车用钢对节能减排具有重要意义。目前正在研发的第三代先进高强钢包括轻质(Lightweight)钢、Q&P(Quenching and partitioning)钢和中锰钢(Mn质量分数为5%~10%)。其中,Fe-Mn-Al-C系低密度高强钢由于Al元素的加入,在密度降低的同时保持着良好的力学性能,满足第三代汽车用钢对轻量化的要求。同时,由于大量Al、Mn和C元素的添加,Fe-Mn-Al-C系低密度钢的冶炼连铸、微观结构、变形机制、加工过程及应用性能与传统钢种大不相同。本文系统阐述了Fe-Mn-Al-C系低密度钢的成分设计及其中合金元素的作用,介绍了低密度钢的微观组织结构特征;重点讨论了单一铁素体钢、奥氏体基钢、奥氏体基双相钢和铁素体基双相钢的各种强韧化机制,包括固溶强化、细晶强化、沉淀强化及其独特的应变硬化机制,如相变诱导塑性(TRIP)、孪晶诱导塑性(TWIP)、微带诱导塑性(MBIP)、剪切带诱导塑性(SIP)和动态滑移带细化(DSBR)等;并就层错能(SFE)对奥氏体钢变形机制产生的影响进行了总结;最后,对Fe-Mn-Al-C系低密度钢的强韧化机制研究进行展望,为后续研究者的工作提供参考。展开更多
基金financially supported by the National Natural Science Foundation of China(No.51261013)。
文摘The chemical stability,electronic structures,mechanical properties and Debye temperature of Fe-MnAl alloys were investigated using first-principles calculations.The formation enthalpy and cohesive energy are negative for Fe-Mn-Al alloys,showing that they are thermodynamically stable.FeAl has the lowest formation enthalpy,indicating that FeAl is the most stable alloy in the Fe-Mn-Al system.The partial density of states,total density of states and electron density distribution maps were used to analyze the physical properties of the Fe-MnAl alloys.A combination of mainly covalent and metallic bonds exists in these Fe-Mn-Al alloys,resulting in good electronic conductivity,high melting points,and high hardness.These alloys display disparate anisotropy due to the calculated different shapes of the 3D curved surface of the Young's modulus and anisotropic index.FeAl has the highest bulk modulus,shear modulus and Yong's modulus of 187.1,119.8 and 296.2 GPa,respectively.Further,the Debye temperatures and sound velocity of these Fe-Mn-Al compounds were explored.
文摘Phase equilibria at Fe-Mn side of isothermal section at 1000 and 1100℃ in Fe-Mn- Al system have been determined using the diffusion couple technique and metallography. A three-phase,α+γ+β,region was found at 1000℃.The method of solid/gas diffusion couple used to determine equilibrium phase composition is believed to be feasible for the system containing volatile component.
文摘汽车行业的迅速发展使得能源消耗、环境污染等问题日益严重,而开发高强度且轻量化的汽车用钢对节能减排具有重要意义。目前正在研发的第三代先进高强钢包括轻质(Lightweight)钢、Q&P(Quenching and partitioning)钢和中锰钢(Mn质量分数为5%~10%)。其中,Fe-Mn-Al-C系低密度高强钢由于Al元素的加入,在密度降低的同时保持着良好的力学性能,满足第三代汽车用钢对轻量化的要求。同时,由于大量Al、Mn和C元素的添加,Fe-Mn-Al-C系低密度钢的冶炼连铸、微观结构、变形机制、加工过程及应用性能与传统钢种大不相同。本文系统阐述了Fe-Mn-Al-C系低密度钢的成分设计及其中合金元素的作用,介绍了低密度钢的微观组织结构特征;重点讨论了单一铁素体钢、奥氏体基钢、奥氏体基双相钢和铁素体基双相钢的各种强韧化机制,包括固溶强化、细晶强化、沉淀强化及其独特的应变硬化机制,如相变诱导塑性(TRIP)、孪晶诱导塑性(TWIP)、微带诱导塑性(MBIP)、剪切带诱导塑性(SIP)和动态滑移带细化(DSBR)等;并就层错能(SFE)对奥氏体钢变形机制产生的影响进行了总结;最后,对Fe-Mn-Al-C系低密度钢的强韧化机制研究进行展望,为后续研究者的工作提供参考。
