Neutron diffraction analysis of stress and strain partitioning in a two-phase microstructure with parallel-aligned phases
Neutron diffraction analysis of stress and strain partitioning in a two-phase microstructure with parallel-aligned phases
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DOI：
10.1038/s41598-020-70299-1
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发表时间：
2020-08-11
影响因子：
4.6
通讯作者：
Mola, Javad
中科院分区：
文献类型：
--
作者：
Huang, Qiuliang;Shi, Ran;Mola, Javad
通过飞行时间中子衍射实验，研究了奥氏体（γ）和马氏体（α '）相的偏析诱导组织带对应力应变分配的影响。首先，通过淬火和分配（Q&P）处理对添加Co的不锈钢的拉伸试样进行热处理。拉伸试样随后在350 ℃下平行于相混合物的表观弹性极限内的带的长度加载。在轴向和横向方向的晶格参数同时测量两个阶段。在横向方向上的γ相的晶格膨胀的观察表明，由带状显微组织产生的γ的自由横向应变的约束。α '的横向收缩在γ相的横向方向上施加了一个相间拉伸微应力。多轴向应力状态在伽马阶段的发展导致了一个大的偏离单轴加载单相伽马预期的塑性应变水平。由于在许多工程合金中普遍存在偏析诱导的带状显微组织，因此本Q&P钢的应力和应变分配分析可用于解释对具有两相显微组织的其他工程合金所做的观察。
By time-of-flight (TOF) neutron diffraction experiments, the influence of segregation-induced microstructure bands of austenite (gamma) and martensite (alpha ' ) phases on the partitioning of stress and strain between these phases was investigated. Initially, tensile specimens of a Co-added stainless steel were heat treated by quenching and partitioning (Q&P) processing. Tensile specimens were subsequently loaded at 350 degrees C parallel to the length of the bands within the apparent elastic limit of the phase mixture. Lattice parameters in both axial and transverse directions were simultaneously measured for both phases. The observation of a lattice expansion for the gamma phase in the transverse direction indicated a constraint on the free transverse straining of gamma arising from the banded microstructure. The lateral contraction of alpha ' imposed an interphase tensile microstress in the transverse direction of the gamma phase. The multiaxial stress state developed in the gamma phase resulted in a large deviation from the level of plastic strain expected for uniaxial loading of single phase gamma. Since segregation-induced banded microstructures commonly occur in many engineering alloys, the analysis of stress and strain partitioning with the present Q&P steel can be used to interpret the observations made for further engineering alloys with two-phase microstructures.