冲击拉伸加载下等轴TiAl的微观组织演化行为  

Microstructure evolvement of isometry TiAl under tensile impact loadings

作　　者：昝祥[1] 贺跃辉[2] 卢正欣[3] 汪洋[4] 夏源明[1] 

机构地区：[1]合肥工业大学材料科学与工程学院,合肥230009 [2]中南大学粉末冶金国家重点实验室,长沙410083 [3]西安理工大学材料科学与工程学院,现代分析测试中心,西安710048 [4]中国科学技术大学近代力学系中国科学院材料力学行为和设计重点实验室,合肥230027

出　　处：《粉末冶金材料科学与工程》2011年第1期13-19,共7页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金资助项目(10902106,90505002)

摘　　要：通过对等轴组织的Ti-46.5Al-2Nb-2Cr在不同温度和应变率下的力学行为和变形机理研究,揭示应变率对其变形机理的影响。利用冲击拉伸实验研究等轴TiAl在不同温度下的动态力学行为。研究结果表明：等轴TiAl的强度是与温度和应变率相关的;动载下的强度明显高于静载下的强度,但在高应变率范围内（320~1 350 s-1）无明显的应变率相关性;动载下的韧脆转变温度较静载下的韧脆转变温度高。透射电镜（TEM）分析表明高应变率加载下,等轴TiAl的变形主要受层错和孪生机制的控制,而在准静态加载条件下,位错运动机制是主要的变形方式。Through study on the mechanical behavior and deformation mechanism of Ti-46.5Al-2Nb-2Cr alloy at different temperature and strain rate,the effects of strain rate on the deformation mechanism of isometric TiAl（NG TiAl） were explored.The dynamic mechanical behavior of TiAl was tested by tensile impact loadings experiment.The results show that the strength of TiAl is strain rate and temperature dependent.The dynamic strength of TiAl is higher than that under quasi-static loadings but is not sensitive to strain rate under high strain rate loading range of 320~1 350 s-1.The brittle-to-ductile temperature（BDTT） under high strain rate loadings is higher than that under quasi-static loadings.TEM investigation indicates that deformation twinning and/or stacking fault are the main deformation modes of isometric TiAl under high strain rate loadings while the dislocation movement is another mechanism under quasi-static loadings.

关 键 词：TIAL金属间化合物 高应变率 高温 力学行为 微观组织 

分 类 号：TH142.2[一般工业技术—材料科学与工程]