(1. 安徽理工大学 材料科学与工程学院，淮南 232001；
2. 中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 本文通过配置72个四元合金，利用X射线衍射(XRD)和扫描电子显微镜(SEM/EDS)测定了高强β型钛合金Ti-Al-Mo-V-Cr体系中关键四元系Ti-Al-Mo-V、Ti-Al-Mo-Cr和Ti-Al-V-Cr含20 % Al (摩尔分数)时700和800 ℃的相平衡关系。实验结果表明：Ti-Al-Mo-V体系存在3个两相区(AlTi3+BCC_A2、AlMo3+BCC_A2、BCC_A2#1+BCC_A2#2)和1个单相区(BCC_A2)；Ti-Al-Mo-Cr体系存在1个四相区(AlMo3+BCC_A2#1+BCC_A2#2+Laves_C14)、2个三相区(AlMo3+BCC_A2+Laves_C14、AlTi3+BCC_A2+Laves_C14)、3个二相区(AlTi3+BCC_A2、AlMo3+BCC_A2、Laves_C14+BCC_A2)和1个单相区(BCC_A2)；Ti-Al-Cr-V体系存在1个三相区(AlTi3+BCC_A2+Laves_C14)、3个两相区(AlTi3+BCC_A2、AlMo3+BCC_A2、Laves_C14+BCC_A2)和1个单相区(BCC_A2)。根据实验结果，本文构筑了这些四元系含20 % Al时700和800 ℃的等温截面，为设计新型β钛合金提供重要的理论指导。
关键字: Ti-Al-Mo-V-Cr；钛合金；相平衡；相图；实验测定
（1. School of Materials Science and Engineering, Anhui University of Science and Technology, Huainan 232001, China;
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:Seventy-two quaternary alloys were prepared to investigate the phase equilibria of the Ti-Al-Mo-V, Ti-Al-Mo-Cr and Ti-Al-V-Cr systems at 700 and 800 ℃ with 20% (mole fraction) Al in the high strength β titanium alloy Ti-Al-Mo-V-Cr system by combining X-ray diffractometry (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) in the present work. The results show that there are three two-phase regions (AlTi3+BCC_A2, AlMo3+BCC_A2, BCC_A2#1+BCC_A2#2) and one single-phase region (BCC_A2) in Ti-Al-Mo-V system, one four-phase region (AlMo3+BCC_A2#1+BCC_A2#2+ Laves_C14) and two three-phase regions (AlMo3+BCC_A2+Laves_C14, AlTi3+BCC_A2+Laves_C14), three two-phase regions (AlTi3+BCC_A2, AlMo3+BCC_A2, Laves_C14+BCC_A2) and one single-phase region (BCC_A2) in Ti-Al-Mo-Cr system, and one three-phase region (AlTi3+BCC_A2+Laves_C14), three two-phase regions (AlTi3+BCC_A2, AlMo3+BCC_A2, Laves_C14+BCC_A2) and one single-phase region (BCC_A2) in the Ti-Al-V-Cr system at 700 and 800 ℃. The isothermal sections of these quaternary systems at 700 and 800 ℃ with 20% (mole fraction) Al are constructed, which are provided important theoretical guidance for designing new β titanium alloys.
Key words: Ti-Al-Mo-V-Cr; titanium alloy; phase equilibria; phase diagram; experimental determination
