时效温度对Ti1023和Ti5553合金微观组织与析出硬化的影响规律  

Effect of Aging Temperature on Microstructures and Precipitation Hardening in Ti1023 and Ti5553 Alloys

作　　者：王文婷 李沛 寇文娟[1] 孙巧艳[1] 刘彬[2] 肖林[1] 孙军[1] Wang Wenting;Li Pei;Kou Wenjuan;Sun Qiaoyan;Liu Bin;Xiao Lin;Sun Jun(State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China;State Key Laboratory for Powder Metallurgy,Central South University,Changsha 410083,China)

机构地区：[1]西安交通大学金属材料强度国家重点实验室,陕西西安710049 [2]中南大学粉末冶金国家重点实验室,湖南长沙410083

出　　处：《稀有金属材料与工程》2020年第5期1707-1714,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51671158,51621063);国家重点基础研究发展计划(“973”计划)(2014CB644003);高等学校学科创新引智计划2.0(PB2018008)。

摘　　要：研究了Ti1023和Ti5553钛合金经过固溶与低温时效处理(ST-SQA)获得的微观组织和析出硬化行为。采用扫描电镜和透射电镜观察了不同温度时效处理后α相的析出形貌以及分布特点,统计了时效析出次生α相的析出密度和宽度随时效温度的变化情况,并测试了合金的维氏硬度。结果表明:Ti1023合金时效处理时次生α的析出温度低于Ti 5553合金。Ti1023合金在300℃时效时α相已经析出,400℃时效时α相析出密度到达峰值;Ti5553合金在450~500℃时效α相开始析出,在550℃时效α相的析出密度达到峰值。Ti1023合金硬度随着时效温度的增加先升后降,400℃时效硬度最高;在相同的时效温度范围,Ti5553合金硬度变化出现双峰规律,硬度峰值分别对应于350和550℃时效温度。2种合金的硬度变化规律源于合金时效中第二相的析出行为:时效温度低于400℃,Ti1023合金的硬度取决于α相和ω相,而Ti5553合金的硬度取决于ω相;时效温度高于400℃,2种合金的硬度均主要取决于次生α相的数量与尺寸。The microstructures and precipitation hardening of Ti1023 and Ti5553 alloys after the same solution treatment and step-quench aging treatment(ST-SQA) have been studied. The morphology of α phase about precipitation and distribution in different aging treatment were observed by using SEM and TEM, and the variation of density and width of secondary α phase were analyzed. The hardness of these two alloys was measured. The result shows that Ti1023 alloy is more likely to precipitate α phase than Ti5553 alloy due to low stability of β phase. Ti1023 alloy precipitates α phase at 300℃ aging and gets the maximum density of precipitation at 400℃, while Ti5553 alloy precipitates α phase at 450℃, and gets the maximum density of precipitation at 550℃. As for Ti1023 alloy, the peak of hardness is obtained at 400℃ aging, while as for Ti5553 alloy, double peaks of hardness are shown at 350℃ and 550℃ aging. The variation of hardness was caused by the precipitation of secondary phase in β phase for different aging temperatures. When aging temperature is below 400℃, the hardness of Ti1023 alloy depends on both α phase and ω phase, and the hardness of Ti5553 alloy depends on only ω phase. As aging temperature is over 400℃, the hardness of both Ti1023 and Ti5553 alloys depend on the density of precipitation and the size of α phase.

关 键 词：高强β钛合金 次生α相 时效 硬化 

分 类 号：TG146.23[一般工业技术—材料科学与工程]