热成形条件下TC4钛合金的相变特征

以钛合金TC4为例评述了热成形条件下金属固态相变特征、影响因素和相变规律的研究现状,讨论了工艺条件、相变过程、微观组织与力学性能之间的因果关系. 指出传统相变研究没有考虑塑性变形对相变的影响,因而不能用于分析热成形过程中相变对热塑性加工零件微观组织和力学性能的影响. 给出了作者近期得到的TC4钛合金变形与相变的实验结果;结果证明,热塑性变形对相变有明显影响,主要表现为应变速率增加会对相变有阻止作用,应变增加对相变有促进作用.

Phase Transformation of TC4 Titanium Alloy During Hot Forming

A review on the basic characters, influence factors and evolution law of the metal solid phase transformation during hot forming was presented by taking titanium alloy TC4 as an example and the causal chain of the process parameters, phase transformation, microstructure and mechanical behaviors were discussed. It is pointed out that the traditional theory of phase transformation does not include the influence of plastic deformation on phase transformation, and could not be applied for analysis of microstructure evolution and mechanical behaviors of the work piece during hot plastic forming. The experimental results on TC4 alloy phase transformation during hot deformation provided here show the significant influences of hot plastic deformation on phase transformation. An increase in strain rate may hinder phase transformation, and an increase in strain may promote phase transformation.