Tensile properties and microstructure of Ti14 alloy after semi-solid forging  

半固态锻造Ti14合金的拉伸性能和组织演变特征(英文)

作　　者：陈永楠[1] 魏建锋[2] 赵永庆[3] 张学敏[1] 

机构地区：[1]长安大学材料科学与工程学院,西安710064 [2]西安交通大学金属材料强度国家重点实验室,西安710049 [3]西北有色金属研究院,西安710016

出　　处：《Transactions of Nonferrous Metals Society of China》2011年第12期2610-2616,共7页中国有色金属学报（英文版）

基　　金：Projects (2005CCA06400, 2007CB613807) supported by the National Basic Research Program of China;Project (CHD2012JC078) supported by the Special Fund for Basic Scientific Research of Central Colleges, China;Project (0111201) supported by the State Key Laboratory for Machanical Behavior of Materials;Project (20110474) supported by Natural Science Basic Research Plan in Shaanxi Province of China

摘　　要：Tensile properties of a new α＋Ti2Cu alloy after solid forging at 950 °C and semi-solid forging at 1 000 °C and 1 050 °C were investigated over the temperature range of 20-600 °C. The results reveal that high strength and low ductility are obtained in all semi-solid forged alloys. Tensile properties decrease as the semi-solid forging temperature increases, and cleavage fractures are observed after semi-solid forging at 1 050 °C. The variations in tensile properties are attributed to the coarse microstructures obtained in the semi-solid alloys. It is found that the elevated semi-solid temperatures lead to more liquid precipitates along the prior grain boundaries, which increases the peritectic precipitation and formation of Ti2Cu precipitation zones during re-solidification. Recrystallization heat treatment leads to fine microstructure of semi-solid forged alloys, resulting in improvement of tensile properties.通过室温和高温拉伸性能测试,对比研究了Ti14合金经常规锻造(950℃)和半固态锻造(1000℃和1050℃)后试样在不同温度区间的宏观力学行为,分析了微观组织演变规律、断口微观形貌及断裂特征。结果表明:合金经半固态锻造后表现出高强度、低塑性的力学特征,随着半固态锻造温度的升高,合金力学性能下降。半固态锻造过程中组织的变化是引起力学性能差异的主要原因,而组织演变的主要特征是Ti2Cu析出相形态和分布的变化。随着半固态温度的升高,更多的液相在晶界析出,并在凝固过程中析出大量板条状Ti2Cu相,最终在晶界上形成偏析带组织。这种带状组织在拉伸过程中引发了解离断裂,导致了低塑性。此外,通过再结晶退火可以有效地细化半固态组织,改善强度性能。

关 键 词：Ti14 alloy semi-solid forging MICROSTRUCTURE tensile properties heat treatment 

分 类 号：TG146.23[一般工业技术—材料科学与工程]