片层组织特征对Ti-6Al-4V-4Zr-Mo合金准静态及动态变形行为的影响(英文)

Effects of Lamellar Microstructure Characteristics on Quasi-static and Dynamic Deformation Behavior of Ti-6Al-4V-4Zr-Mo Alloys

对片层组织的新型钛合金(Ti-6Al-4V-4Zr-Mo)进行时效处理,通过改变时效温度控制其微观组织细节特征,对具有不同组织特征的试样进行微观组织观察、力学性能测试以及断口分析,研究了片层组织细节特征对Ti-6Al-4V-4Zr-Mo合金准静态拉伸性能和动态压缩性能的影响。结果表明:对β固溶处理后的Ti-6Al-4V-4Zr-Mo合金进行后续时效处理,随着时效温度的降低,网篮结构排列更为密集,α集束尺寸、α片层厚度以及β组织基体上析出的针状次生α相的尺寸均明显减小;随着时效温度的降低,片层组织的准静态、动态塑性均增加;经570℃时效处理后得到的网篮组织,α集束尺寸以及集束中α片层尺寸较小,且β组织基体上有许多细小的针状次生α片层析出,使得位错的滑移距离减小同时使得裂纹扩展路径更曲折,在维持一定静、动态强度的同时,其静、动态塑性明显改善,表现出良好的综合力学性能。

The influences of lamellar microstructure characteristics on quasi-static tensile properties and dynamic compression deformation behavior were studied for newly developed titanium alloy Ti-6Al-4V-4Zr-Mo.To tailor the microstructure characteristics,the lamellar microstructure was obtained by be solution treatment at 960 ℃ and underwent subsequent aging treatments at 700 and 570 ℃,respectively.Results show that as the aging temperature decreases,the size of α colonies and the width of α plates present a declining trend.Correspondingly,the slip length of dislocation becomes relatively shorter,resulting in the increase of quasi-static deformation capability.Dynamic compression tests also show that the lamellar microstructure aged at 570 ℃ with α colonies and α plates in smaller size,which induces the propagated path of crack easily bifurcate and deflect,presents higher dynamic fracture strain,in contrast with the lamellar microstructure aged at 700 ℃.