Flow behavior and microstructure in Ti-6Al-4V alloy with an ultrafine-grained α-single phase microstructure during low-temperature-high-strain-rate superplasticity
Flow behavior and microstructure in Ti-6Al-4V alloy with an ultrafine-grained α-single phase microstructure during low-temperature-high-strain-rate superplasticity
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DOI：
10.1016/j.matdes.2014.05.045
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发表时间：
2015-02-05
影响因子：
8.4
通讯作者：
Chiba, Akihiko
中科院分区：
文献类型：
--
作者：
Matsumoto, Hiroaki;Velay, Vincent;Chiba, Akihiko
细化Ti-6Al-4V合金(以下简称Ti-合金)被公认为是揭示低温或高应变速率超塑性的一种方法。本文研究了超细晶钛-合金(d(α)=0.4µm)在700℃变形过程中的超塑性流动行为与组织演变的关系。详细的微观组织分析表明，变形初期的Ball-Hutchison模型和变形后期的Gifkins Core-Mantle模型可以合理地解释晶界滑移的超塑性变形模式(700℃-10(-2)S(-1))。在超塑性变形过程中，会产生β-析出，并对晶界应力集中的调节机制作出贡献。根据Bird-Mukherjee-Dorn(BMD)广义本构关系和考虑变形过程中动态晶粒长大影响的模型，讨论了超塑性流动行为与Bird-Mukherjee-Dorn(BMD)广义本构关系下的流动行为。(C)2014爱思唯尔有限公司。保留所有权利。
Grain refinement of Ti-6Al-4V alloy (hereafter designated as Ti-64 alloy) is well recognized as a method for revealing the superplasticity at lower temperature or higher strain rates. This work examines the superplastic flow behavior of the ultrafine-grained (UFG) Ti-64 alloy (d(alpha) = 0.4 mu m) consisting of single a phase in relation to microstructural evolution during deformation at 700 degrees C. Detailed microstructural evaluation reveals that the superplastic deformation mode of grain boundary sliding (tested at 700 degrees C-10(-2) s(-1)) can be reasonably explained in relation to the Ball-Hutchison model at initial stage of deformation and the Gifkins Core-Mantle model at latter stage of deformation. During superplastic deformation, the beta-precipitation occurs and contributes to accommodation mechanism of stress concentration at grain boundaries. This work also discusses the superplastic flow behavior in comparison with flow behaviors according to the Bird-Mukherjee-Dorn (BMD) generalized constitutive relation and the model which considers the effect of dynamic grain growth during deformation. (C) 2014 Elsevier Ltd. All rights reserved.