TA15钛合金近β变形三态组织中片状α演化规律  

Evolution Mechanism of Lamellar α in Tri-Modal Microstructure of TA15 Ti-Alloy during Near β Deformation

作　　者：马超[1] 孙志超[1] 韩飞孝 杨合[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《稀有金属材料与工程》2015年第7期1661-1667,共7页Rare Metal Materials and Engineering

基　　金：国家重点基础研究发展计划("973"计划)(2010CB731701);国家自然科学基金重点/面上项目(50935007;51275560);教育部"新世纪优秀人才支持计划(NCET-12-0468);"111"引智计划(B08040)

摘　　要：近β变形+热处理工艺为TA15钛合金获得三态组织提供了一种可行途径,作为三态组织的重要组成部分并决定其损伤容限性能的片状α是在近β变形和后续热处理共同作用下产生的,其演化过程十分复杂,而三态组织对各相特别是片状α的含量和形态要求苛刻。本研究采用热模拟压缩实验和定量金相实验研究了不同近β变形条件下(变形温度、变形程度和应变速率)TA15钛合金变形+高低温强韧化热处理(950℃/100 min/WQ+800℃/8 h/AC)后微观组织演化行为,揭示了组织中片状α含量和形貌的演化规律;在此基础上,以高损伤容限性能为目标,研究确定了获得满足三态组织要求并具有优异断裂性能的片状α近β变形条件区间;实验和理论分析表明:针对TA15钛合金,在所确定的近β变形区间内可以获得性能优异的三态组织。研究结果可为TA15钛合金通过近β变形工艺获得三态组织和性能优化的片状α提供指导。Near-β deformation combined with subsequent heat treatment process provides a possible way to obtain the tri-modal microstructure for TA15 Ti-alloy.As an important component of tri-modal microstructure, the evolution of lamellar α, which determines damage tolerance properties, is complex and difficult to control in the process of near β deformation and subsequent heat treatment.At the same time, the tri-modal microstructure has strict requirements on the composition and morphology of final microstructure, especially on lamellar α.In this paper the microstructure evolution behavior of TA15 Ti-alloy after deformation and 950 ℃, 100 min, WQ＋800 ℃, 8 h, AC under different deformation conditions（deformation temperature, deformation degree and strain rate） were investigated via the thermal simulation test and metallographic test.The evolution mechanism of lamellar α in tri-modal microstructure was revealed.Based on the obtained results, taking high damage tolerance as target, the reasonable range of near β deformation condition were determined to obtain lamellar α possessing excellent fracture toughness and microstructure meeting requirement of tri-modal microstructure.Experimental and theoretical analyses show that for TA15 Ti-alloy the tri-modal microstructure of excellent performance could be obtained within the deformation condition range.The results can provide a guide for obtaining the tri-modal microstructure and excellent lamellar α via near-β deformation processing.

关 键 词：TA15钛合金 三态组织 近Β锻造 热处理 片状α 

分 类 号：TG146.23[一般工业技术—材料科学与工程]