摘要
Split Hopkinson Tension Bar(SHTB) experiments were conducted to explore the dynamic mechanical behavior and deformation mechanism of powder metallurgical(PM) Ti-47 Al-2 Nb-2 Cr-0.2 W(at.%)intermetallics with near lamellar(NL) and duplex(DP)microstructures. Results show that,under dynamic loading,the high temperature strength of the PM TiAl intermetallics is higher than that under quasi-static loading, and the ductile to brittle transition temperature(DBTT) increases with the increase of strain rate. Formation of twinning and stacking faults is the main deformation mechanism during dynamic loading. The work hardening rates of the PM TiAl intermetallics are nearly insensitive to strain rate and temperature at high strain rates(800-1600 s-1)and high temperatures(650-850 ℃). Zerilli-Armstrong model is successfully used to describe the dynamic flowing behavior of the PM TiAl intermetallics. In general, the PM TiAl intermetallics are found to have promising impact properties, suitable for high-temperature and high-impact applications.
采用分离式霍普金森拉杆动态冲击变形实验研究粉末冶金Ti-47Al-2Nb-2Cr-0.2W (at.%)双态组织和近层片组织在高应变率下(800~1600 s-1)的动态力学行为和变形机理。结果表明,粉末冶金TiAl金属间化合物的韧性-脆性转变温度(DBTT)随应变速率增加而增大,动态加载下两种组织的高温强度均高于准静态加载下的高温强度;在高应变速率(800~1600s-1)和高温(650~850℃)条件下,粉末冶金TiAl金属间化合物的双态组织和近层片组织的加工硬化速率均对应变速率和温度不敏感。在动态加载条件下,堆垛层错及孪晶的形成是主要的变形机制。Zerilli-Armstrong模型能够恰当描述粉末冶金TiAl金属间化合物的高温动态变形行为。
基金
Project(51774335)supported by the National Natural Science Foundation of China
Project(2017JJ2311)supported by the Natural Science Foundation of Hunan Province,China
Project(KFJJ11-7M)supported by the Opening Project of State Key Laboratory of Explosion Science and Technology,China
Project(HKHTZD20140702020004)supported by the Special Funds for Future Industrial Development of Shenzhen City,China
