Strain localization and damage in dual phase steels investigated by coupled in-situ deformation experiments and crystal plasticity simulations
Strain localization and damage in dual phase steels investigated by coupled in-situ deformation experiments and crystal plasticity simulations
复制标题
DOI：
10.1016/j.ijplas.2014.06.004
复制
发表时间：
2014-12-01
影响因子：
9.8
通讯作者：
Raabe, D.
中科院分区：
文献类型：
--
作者：
Tasan, C. C.;Hoefnagels, J. P. M.;Raabe, D.
铁素体-马氏体双相（DP）钢在空间上以高度不均匀的方式变形，即在微观尺度上具有强烈的应变和应力分配。这种局部应变演化的不均匀性反过来又导致了损伤分布的空间不均匀性，从而在损伤遗传和断裂过程中起着重要的作用。为了理解和改进DP钢，重要的是要确定观察到的应变和损伤不均匀性与潜在的微观结构参数之间的联系，例如铁素体晶粒尺寸，马氏体分布，马氏体分数等。在这项工作中，我们通过对两种不同的DP钢等级进行原位变形实验来实现这一目标，采用两种不同的显微数字图像相关（μ DIC）技术，以实现具有代表性的统计和高分辨率的微观结构应变图。结合观察到的损伤事件（通过图像后处理识别）和局部应力图（从相同微观结构区域的晶体塑性（CP）模拟中获得）分析所得的局部应变图。结果表明，塑性通常在具有较大铁素体晶粒和较低局部马氏体分数的“热区”内开始。随着全球变形的增加，破坏事件最经常观察到的边界，这样的高度塑化区。高分辨率mu DIC和相应的CP模拟揭示了马氏体弥散的重要性：在材料的全部应变硬化能力消耗之前，具有大块马氏体的区域更容易发生宏观局部化。总体而言，所提出的联合分析建立了一个集成的计算材料工程（ICME）方法设计先进的DP钢。(C)2014爱思唯尔有限公司版权所有。
Ferritic-martensitic dual phase (DP) steels deform spatially in a highly heterogeneous manner, i.e. with strong strain and stress partitioning at the micro-scale. Such heterogeneity in local strain evolution leads in turn to a spatially heterogeneous damage distribution, and thus, plays an important role in the process of damage inheritance and fracture. To understand and improve DP steels, it is important to identify connections between the observed strain and damage heterogeneity and the underlying microstructural parameters, e.g. ferrite grain size, martensite distribution, martensite fraction, etc. In this work we pursue this aim by conducting in-situ deformation experiments on two different DP steel grades, employing two different microscopic-digital image correlation (mu DIC) techniques to achieve microstructural strain maps of representative statistics and high-resolution. The resulting local strain maps are analyzed in connection to the observed damage incidents (identified by image post-processing) and to local stress maps (obtained from crystal plasticity (CP) simulations of the same microstructural area). The results reveal that plasticity is typically initiated within "hot zones" with larger ferritic grains and lower local martensite fraction. With increasing global deformation, damage incidents are most often observed in the boundary of such highly plastified zones. High-resolution mu DIC and the corresponding CP simulations reveal the importance of martensite dispersion: zones with bulky martensite are more susceptible to macroscopic localization before the full strain hardening capacity of the material is consumed. Overall, the presented joint analysis establishes an integrated computational materials engineering (ICME) approach for designing advanced DP steels. (C) 2014 Elsevier Ltd. All rights reserved.