Ways to Fabricate Ultrafine Grained Steels
特邀嘉宾：Nobuhiro Tsuji 教授
Ultrafine grained (UFG) metallic materials of which mean grain sizes are smaller than 1 μm have been studied energetically since it was found that ultra-high strain deformation (severe plastic deformation: SPD) could realize UFG structures in almost all metallic materials. However, it is still difficult to apply the SPD processes which require special equipment and a little bit complicated procedures to large-scale fabrication of bulky metals, typically in steel industries. In the present invited talk, the speaker will show the mechanism why UFG microstructures could be obtained by SPD firstly, and then introduce the original processes for realizing UFG structures in steels without SPD, which are developed in speaker’s group and applicable to conventional thermomechanical processing routes. Insome cases the fully recrystallized UFG structures could be obtained, which were favorable for both strength and ductility.
嘉宾简介：日本京都大学材料科学与工程系教授。主要从事金属结构材料(钢、有色金属)和纳米结构材料的微观结构、力学性能、加工工艺、物理冶金等方面的研究。日本金属学会(JIM) 、日本钢铁协会(ISIJ)、TMS、ASM、AIST、MRS、MRS-J、日本轻金属研究院、日本焊接学会等会员。作为ARB叠轧的创始人，Nobuhiro Tsuji教授已发表论文超过400篇，论文引用超过9000次，h因子44。
报告二：Effect of Grain Size on Hydrogen Embrittlement Behaviors in TWIP steels
Twinning induced plasticity (TWIP) steels show an excellent combination of high strength and large ductility. In the speaker`s group, ultrafine-grained (UFG) TWIP steels with grain size of under 1 μm were fabricated by conventional cold-rolling and subsequent annealing. The UFG TWIP steels show high strength and large ductility, which match the demand of the automotive industries to fabricates high strength and light weight structural materials. In general, the susceptibility to hydrogen embrittlement increases with increasing the strength, which causes great damage to the structural materials. However, the hydrogen embrittlement behaviors of UFG TWIP steels are not fully understood yet. In the present talk, the effect of grain size on hydrogen embrittlement behaviors in TWIP steels will be shown in detail.
讲座时间: 2016年11月14日（星期一）上午9 :30-11 :30