新型多相TiAl合金的β/B2相含量变化及其对拉伸性能的影响  

β/B2 phase content change and its effect on tensile properties of novel multiphase TiAl alloy

作　　者：冯像征 高帆 刘宏武 李臻熙 FENG Xiangzheng;GAO Fan;LIU Hongwu;LI Zhenxi(AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China)

机构地区：[1]中国航发北京航空材料研究院,北京100095

出　　处：《航空材料学报》2024年第4期96-108,共13页Journal of Aeronautical Materials

基　　金：中国航发科技创新平台项目(CXPT-2021-030);中国航发自主创新专项资金项目(ZZCX-2022-035)。

摘　　要：以新型多相TiAl合金(Ti-43.5Al-6(Nb、Cr、Ta))的挤压态组织为研究对象,先通过热处理分析该合金中β/B2相、α/α2相和γ相平均含量随固溶温度和保温时间的演变规律,然后测试合金在三相区内不同β/B2相含量时的室温和高温(750℃和800℃)拉伸性能。结果表明:在1190~1350℃范围内,γ相含量随固溶温度的升高和保温时间的延长逐渐减少,在1270℃时,γ相完全消失;在1190~1350℃范围内,β/B2相含量随固溶温度的升高先减少后增加,随保温时间的延长逐渐减少,而层片团的含量和尺寸与β/B2相的含量变化负相关;在1230~1280℃范围内,β/B2相平均含量可控制在10%以下;在1250~1270℃范围内,延长保温时间可将β/B2相平均含量控制在0.5%以下;当合金处于三相区时,控制β/B2相平均含量约6%,可得到综合拉伸性能优异的均匀细小近层片组织,且该组织的室温抗拉强度超过1050 MPa、室温伸长率1.5%~2%,750℃抗拉强度超过950 MPa,800℃抗拉强度超过850 MPa。The as-extruded microstructure of novel multiphase TiAl alloy(Ti-43.5Al-6(Nb,Cr,Ta))was taken as the research object,the evolution of the average content ofβ/B2 phase,α/α2 phase andγphase in this alloy with the solution temperature and holding time was analyzed by heat treatment,and then the tensile properties of the alloy at room temperature and high temperature(750℃and 800℃)with differentβ/B2 phase contents were tested.The results show that in the range of 1190℃to 1350℃,the content ofγphase decreases gradually with the increase of solution temperature and holding time,and theγphase disappears completely at 1270℃;the content ofβ/B2 phase first decreases and then increases with the increase of solution temperature,and gradually decreases with the prolongation of holding time,while the content and size of lamellar cluster have a negative correlation with the change ofβ/B2 phase content;The average content ofβ/B2 phase can be controlled below 10%in the range of 1230-1280℃;the average content ofβ/B2 phase can be controlled below 0.5%in the range of 1250-1270℃.When the alloy is in the three-phase region,the average content ofβ/B2 phase is about 6%,and the uniform and fine nearly lamellar structure with excellent comprehensive tensile properties can be obtained,and the tensile strength at room temperature exceeds 1050 MPa,the elongation at room temperature is 1.5%-2%;the tensile strength at 750℃exceeds 950 MPa,and the tensile strength at 800℃exceeds 850 MPa.

关 键 词：多相TiAl合金 β/B2相 变形TiAl合金 细小近层片组织 拉伸性能 

分 类 号：V252.2[一般工业技术—材料科学与工程] TG146.2[航空宇航科学与技术—航空宇航制造工程]