α_2+B2相区等温锻造及热处理对Ti-22Al-25Nb合金组织和性能的影响  

Effect of Isothermal Forging in α_2+ B2 Phase Region and Heat Treatment on the Microstructure and Properties of Ti-22Al-25Nb Alloy

作　　者：梁晓波[1] 马雄[1] 张建伟[1] 程云君[1] 曾卫东[2] 王伟[2] 

机构地区：[1]钢铁研究总院,北京100081 [2]西北工业大学,陕西西安710072

出　　处：《钛工业进展》2018年第1期24-28,共5页Titanium Industry Progress

基　　金：凝固技术国家重点实验室项目(153-Zh-2016)

摘　　要：研究了Ti-22Al-25Nb合金在α2+B2相区等温锻造及不同制度热处理,其显微组织演变规律和室温、高温拉伸性能变化。结果表明:在α2+B2相区等温锻造后显微组织仍由等轴α2相颗粒、O相包裹着的等轴α2相、细小板条状O相与B2基体组成,与原始锻棒组织的区别在于等轴α2相颗粒发生溶解,数量减少,尺寸下降;等温锻造后再在O+B2相区固溶处理的,组织中等轴α2相颗粒分解,由等轴α2/O相颗粒、板条O相和B2基体组成,且随固溶温度升高,板条O相溶解,变粗、变短;等温锻造后经固溶加时效处理时,B2基体中析出二次针状O相,且随时效温度升高,二次针状O相变粗、变短,室温及650℃高温拉伸性能也随时效温度升高,表现为强度降低而塑性提高。The microstructure evolution and tensile properties at room and high temperature of Ti-22 Al-25 Nb alloy after isothermal forging in α_2＋ B2 phase region and different heat treatments were investigated. The results show that the microstructure is still composed of equiaxed α_2 phase grains,equiaxed α_2 phase surrounded by O phase,fine slab O phase and B2 matrix after isothermal forging in α2＋ B2 phase zone. And the difference is that the equiaxed α_2 phase particles dissolve,the number and the size decrease. After the isothermal forging and solid solution treatment in the O＋ B2 phase zone,the equiaxed α_2 phase particles in the microstructure are decomposed and the microstructure consists of axis α_2/O particles,slab O phase and B2 matrix. With the increase of solution temperature,the slab O phase dissolves and becomes thicker and shorter. After isothermal forging ＋ solution treatment ＋ aging treatment,the secondary acicular O phase is precipitated from the B2 matrix,and as the aging temperature increases,the secondary acicular O phase becomes thicker and shorter,and the tensile properties at room temperature and 650 ℃ also increase with the aging temperature,showing the decrease of strength and improvement of plasticity.

关 键 词：TI2ALNB基合金 等温锻造 热处理 组织演变 拉伸性能 

分 类 号：TG146.23[一般工业技术—材料科学与工程]