Huang Qiuliang, Shi Ran, Muránsky Ondrej, Beladi Hossein, Kabra Saurabh, Schimpf Christian, Volkova Olena, Biermann Horst, Mola Javad
Institute of Iron and Steel Technology, Technische Universität Bergakademie Freiberg, Leipziger Str. 34, 09599, Freiberg, Germany.
Institute of Energy Process Engineering and Chemical Engineering, Fuchsmühlenweg 9, 09599, Freiberg, Germany.
Sci Rep. 2020 Aug 11;10(1):13536. doi: 10.1038/s41598-020-70299-1.
By time-of-flight (TOF) neutron diffraction experiments, the influence of segregation-induced microstructure bands of austenite (γ) and martensite (α' ) 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 °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 γ phase in the transverse direction indicated a constraint on the free transverse straining of γ arising from the banded microstructure. The lateral contraction of α' imposed an interphase tensile microstress in the transverse direction of the γ phase. The multiaxial stress state developed in the γ phase resulted in a large deviation from the level of plastic strain expected for uniaxial loading of single phase γ. 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.
通过飞行时间（TOF）中子衍射实验，研究了奥氏体（γ）和马氏体（α'）相的偏析诱导微观结构带对这些相之间应力和应变分配的影响。首先，对添加钴的不锈钢拉伸试样进行淬火和分配（Q&P）处理。随后，在350°C下，在相混合物的表观弹性极限内，沿带的长度方向平行加载拉伸试样。同时测量两相在轴向和横向的晶格参数。γ相在横向方向上的晶格膨胀表明，带状微观结构对γ相的自由横向应变产生了约束。α'相的横向收缩在γ相的横向方向上施加了相间拉伸微应力。γ相中形成的多轴应力状态导致与单相γ单轴加载预期的塑性应变水平有很大偏差。由于偏析诱导的带状微观结构在许多工程合金中普遍存在，因此用目前的Q&P钢进行应力和应变分配分析，可用于解释对具有两相微观结构的其他工程合金的观察结果。
