Lam Tu-Ngoc, Wu Yu-Hao, Liu Chia-Jou, Chae Hobyung, Lee Soo-Yeol, Jain Jayant, An Ke, Huang E-Wen
Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Department of Physics, College of Education, Can Tho University, Can Tho 900000, Vietnam.
Materials (Basel). 2022 Jan 20;15(3):777. doi: 10.3390/ma15030777.
The present work extends the examination of selective laser melting (SLM)-fabricated 15-5 PH steel with the 8%-transient-austenite-phase towards fully-reversed strain-controlled low-cycle fatigue (LCF) test. The cyclic-deformation response and microstructural evolution were investigated via in-situ neutron-diffraction measurements. The transient-austenite-phase rapidly transformed into the martensite phase in the initial cyclic-hardening stage, followed by an almost complete martensitic transformation in the cyclic-softening and steady stage. The compressive stress was much greater than the tensile stress at the same strain amplitude. The enhanced martensitic transformation associated with lower dislocation densities under compression predominantly governed such a striking tension-compression asymmetry in the SLM-built 15-5 PH.
本研究工作将对具有8%瞬态奥氏体相的选择性激光熔化（SLM）制造的15-5 PH钢的研究扩展到完全反向应变控制低周疲劳（LCF）试验。通过原位中子衍射测量研究了循环变形响应和微观结构演变。在初始循环硬化阶段，瞬态奥氏体相迅速转变为马氏体相，随后在循环软化和稳定阶段几乎发生完全的马氏体转变。在相同应变幅值下，压应力远大于拉应力。在压缩状态下，与较低位错密度相关的马氏体转变增强，这主要决定了SLM制造的15-5 PH钢中这种显著的拉压不对称性。
