超高强β钛合金等温相转变特性及力学性能  

Isothermal phase transformation characteristics and mechanical properties of ultra-high strengthβtitanium alloy

作　　者：王庆娟[1] 吴金城 王伟[1] 杜忠泽[1] 尹仁锟 WANG Qing-juan;WU Jin-cheng;WANG Wei;DU Zhong-ze;YIN Ren-kun(School of Metallurgy Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China)

机构地区：[1]西安建筑科技大学冶金工程学院,西安710055

出　　处：《材料工程》2021年第9期94-100,共7页Journal of Materials Engineering

基　　金：陕西省国际合作项目(2019KW-064);西安市科技局项目(2020KJRC0051);陕西省教育厅服务地方专项(19JC025)。

摘　　要：近β钛合金的等温相转变具有多样性和复杂性的特点,对温度敏感性强,直接影响其时效后的力学性能。本工作所用合金为自主研发的Ti-Al-V-Mo-Cr-Zr-Fe-Nb超高强β钛合金,采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、硬度计等分析表征手段对等温处理后合金的微观组织演变及力学性能进行系统研究。结果表明,合金300℃时效时只析出等温ω相,等温ω相随时效时间的延长发生长大。合金400℃时效时先析出等温ω相,随着时效时间的延长,α相依附于ω/β界面处形核。合金500℃时效时无ω相析出,针状α相直接从β基体中析出,呈“V”字形均匀分布在β基体中。400℃时效12 h时抗拉强度为1716.1 MPa,伸长率为2%。500℃时效12 h时抗拉强度为1439.8 MPa,伸长率为9.84%,具有良好的强塑性匹配。Nearβtitanium alloy is widely used in automotive and aerospace industries due to their high strength-to-weight ratio and high corrosion resistance.The nearβtitanium alloy can precipitateωphase andαphase after solution and ageing treatment,the strength of which can be remarkably increased,usually at the expense of ductility.It is one of the most important structural components of load-bearing that usually as aircraft skin,shell plating,main frame,linker and special fastener.The alloy used in this paper is a self-developed Ti-Al-V-Mo-Cr-Zr-Fe-Nb ultra-high-strengthβtitanium alloy,which is a typical nearβtitanium alloy.The characteristic of isothermal phase transformation of nearβtitanium alloys is diversity and complexity,which is sensitive to temperature and directly affects the mechanical properties after ageing.In this paper,the microstructural evolution and mechanical properties of a Ti-Al-V-Mo-Cr-Zr-Fe-Nb ultra-high strengthβtitanium alloy after isothermal treatment were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM)and micro-hardness tester.The results show that only the isothermalωprecipitates are formed during ageing at 300℃,and the size of isothermalωphases increase with the ageing time.The isothermalωprecipitates are first precipitated during ageing at 400℃.With the extension of the ageing time,theαphase nucleation occurs near theω/βinterface.Noαprecipitates are obtained in the alloy aged at 500℃,and needle-likeαprecipitates are directly precipitated from theβmatrix,which is evenly distributed in theβmatrix in a“V”shape.Tensile test shows that the tensile strength of the alloy is 1716.1 MPa and the elongation is 2%after ageing at 400℃for 12 h.The tensile strength of the alloy is 1439.8 MPa and the elongation is 9.84%after ageing at 500℃for 12 h,and has a good combination of strength and toughness.

关 键 词：Β钛合金 ω相析出 相转变 硬化特性 力学性能 

分 类 号：TG166.5[金属学及工艺—热处理]