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

摘要:

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

Abstract:

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 °C and underwent subsequent aging treatments at 700 and 570 °C, 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 °C 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 °C.