固溶时效提高ZTC4钛合金铸件性能研究

Study on Improvement of Properties of ZTC4 Titanium Alloy by SAT

通过对力学性能异常某批次ZTC4钛合金骨架铸件化学成分分析,发现该批次铸件氧含量偏低是造成铸件力学性能不合格的根本原因。采用不同相区氩气冷却固溶处理后,发现经过两种固溶工艺处理后的铸件微观组织均为魏氏组织,都存在α'马氏体、晶界α。晶界都得到不同程度细化。β相固溶后,铸件晶粒明显粗大。β相区固溶时效后钛合金铸件强度较α+β两相区固溶时效高,但塑性有所降低。较快的冷却速度条件下,铸件固溶后易变形。

The analysis of chemical compositions of casting shows that a batch of ZTC4 titanium casting has lower tensile properties that were caused by lower oxygen. The ST （solution treatment） cooled by the argon was carried out at different phase zone. The microstructures of castings after ST were Widmanstaten structure, they both had α＇martensite, grain boundary α, the grain boundaries were both refined after ST. The grain of the casting was coarse after BST（Bete solution treatment）. The casting has higher tensile properties after BST than ABST（Alpha-beta solution treatment）, but it has lower plasticity. The ZTC4 titanium casting was easy to be deformed due to the higher cooling rate in the course of ST.