Microstructure evolution and mechanical properties of heat treated LCB titanium alloy

作     者：Khaled M. IBRAHIM Mansour MHAEDE Lothar WAGNER Khaled M.IBRAHIM;Mansour MHAEDE;Lothar WAGNER

作者机构：Central Metallurgical R&D Institute-CMRDI P.O. Box 87 Helwan Cairo Egypt TU-Clausthal IWW Agricolastr. 6 Clausthal-Zellerfeld Germany 

出 版 物：《Transactions of Nonferrous Metals Society of China》 (中国有色金属学报（英文版）)

年 卷 期：2012年第22卷第11期

页      面：2609-2615页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

主　　题：beta Ti alloy Ti-6.6Mo-4.5Fe-1.5Al alloy fatigue crack ageing secondary α primary α β-grain tensile strength fatigue limit 

摘      要：The influence of ageing time on microstructure and mechanical properties of low-cost beta （LCB） titanium alloy with a chemical composition of Ti-6.6Mo-4.5Fe-1.5Al was investigated. The correlation between microstructure and fatigue crack initiation and growth was also studied. Increasing ageing time tended to increase the volume fraction of the secondary α-precipitates, β-grain size and partial spheroidization of primary α-phase. The maximum tensile strength （1565 MPa） and fatigue limit （750 MPa） were obtained for the samples aged at 500 °C for 0.5 h, while the minimum ones of 1515 MPa and 625 MPa, respectively, were reported for the samples aged at 500 °C for 4 h. The samples aged at 500 °C for 4 h showed a transgranular fracture mode. However, the samples aged at 500 °C for 0.5 h revealed a mixture fracture mode of transgranular and intergranular. The formed cracks on the outer surface of the fatigue samples were found to propagate through the β-grains connecting the primary α-particles existing at the β-grain boundaries.