具有高强高塑性和良好加工硬化行为的新型亚稳β钛合金设计及发展

Design and Development of New β Titanium Alloys with High Strength,Large Ductility and Improved Strain-hardening Behavior

本实验将不锈钢中的TRIP/TWIP效应(TRIP:相变诱发的塑形变形,TWIP:孪晶诱发的塑形变形)引入到β钛合金设计中,采用d-电子设计方法和控制合金电子浓度(e/a)的策略,通过控制合金的β稳定性,设计出具有TRIP/TWIP效应,极好的冷加工性能(冷轧变形率>95%),高强(抗拉强度,UTS:900～1200 MPa),优异塑性(均匀塑性变形能力ε约40%)和良好的加工硬化行为(加工硬化区间超过350 MPa)的Ti-Mo基亚稳β钛合金。显微结构分析表明Ti-Mo基合金在塑性变形过程中产生了应力诱发马氏体相变αy和{332}<113>机械孪晶,这导致合金具有以上优异的性能。

Inspired from the superior mechanical properties of TRIP/TWIP steels（TRIP for transformation induced plasticity and TWIP for twinning induced plasticity）,a new type of metastable β Ti-alloys showing combined TRIP/TWIP effects through controlling the β stability of Ti-alloys was reviewed.The alloys were designed based on the ＂d-electron alloy design method＂ and controlling of electron/atom ratio（e/a）.The results show that so-designed alloys display excellent combination of high strength（ultimate tensile strength 900～1200 MPa）,high ductility（uniform elongation 40%） and improved work-hardening behavior.The detailed microstructural analysis indicates that the superior performances arise from the synergic effects between α？ phase transformation induced plasticity（TRIP） and {332}113 twinning induced plasticity（TWIP）.