Deformation-Induced Microstructural Banding in TRIP Steels
Deformation-Induced Microstructural Banding in TRIP Steels
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DOI：
10.1007/s11661-018-4650-z
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发表时间：
2018-05
期刊：
影响因子：
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通讯作者：
S. Celotto;H. Ghadbeigi;C. Pinna;B. Shollock;P. Efthymiadis
中科院分区：
文献类型：
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作者：
S. Celotto;H. Ghadbeigi;C. Pinna;B. Shollock;P. Efthymiadis
组织不均匀会对先进高强度钢的力学性能产生不利影响。本研究对相变诱发塑性(TRIP)钢进行了研究，探讨了硬质第二相的连续晶界网络(CGBN)的影响，并结合数字图像相关(DIC)技术，展示了在拉伸试验中这些连续晶界网络是如何发展成带状的。这些带是由软铁素体基体的横向收缩形成的，它旋转和位移第二相的CGBN和其中的各个特征，使其与加载方向一致。在变形前已经与加载方向对齐的更广泛的预先存在的CGBN是损伤开始和扩展的最关键的微观结构特征。它们导致沿线的硬质第二相之间形成微空洞，这些第二相聚合并发展成长的宏观裂隙。硬质相，残余奥氏体相和马氏体相，没有被区分，因为发现个别相在这些带的形成中不起作用。研究表明，减少原始组织中硬质第二相CGBN的存在将提高其成形性。
Microstructure inhomogeneities can strongly influence the mechanical properties of advanced high-strength steels in a detrimental manner. This study of a transformation-induced plasticity (TRIP) steel investigates the effect of pre-existing contiguous grain boundary networks (CGBNs) of hard second-phases and shows how these develop into bands during tensile testing usingin situobservations in conjunction with digital image correlation (DIC). The bands form by the lateral contraction of the soft ferrite matrix, which rotates and displaces the CGBNs of second-phases and the individual features within them to become aligned with the loading direction. The more extensive pre-existing CGBNs that were before the deformation already aligned with the loading direction are the most critical microstructural feature for damage initiation and propagation. They induce micro-void formation between the hard second-phases along them, which coalesce and develop into long macroscopic fissures. The hard phases, retained austenite and martensite, were not differentiated as it was found that the individual phases do not play a role in the formation of these bands. It is suggested that minimizing the presence of CGBNs of hard second-phases in the initial microstructure will increase the formability.