In this work,we propose a novel method for testing the dynamic mechanical properties of materials and for in-situ observation at ultra-high temperature (up to 1600 ℃).The experimental devices used include a classical split Hopkinson pressure bar,a MoSi2 heating source for obtaining ultra-high temperature,two piston rods added to complement the double synchronically assembled system and a high speed camera employed to observe the deformation.To verify the ability of the proposed method for operating at ultra-high temperature,we conducted our experiments on TC4 alloy at temperatures ranging from 20 to 1400 ℃ and the strain rate of 2000 s-1,and SiC at temperatures ranging from 20 to 1 200 ℃ and the strain-rate of 250 s-1.The results showed that the peak flow stress of the TC4 alloy specimen drops from 1.6 GPa at room temperature to 150 MPa at 1400 ℃,and the compressive strength of the SiC specimen drops from 250 MPa at room temperature to 220 MPa at 1200 ℃.Furthermore,the high speed images revealed that the oxide layer of the TC4 alloy specimen cracked in air but not in argon,and the initial cracks of the SiC specimen occurred at 80％ of the compressive strength at room temperature and at 99％ of the compressive strength at 1 200 ℃.%提出了一种新的超高温(1600℃)动态力学性能测试及原位图像获取方法:在原有分离式Hopkinson压杆的基础上,利用加热源为MoSi2的超高温炉实现超高温环境,采用两个活塞组成双同步系统,利用高速摄像机记录动态变形过程.为了验证所提方法的可行性,以TC4钛合金和SiC陶瓷为研究对象,进行超高温动态力学性能测试,其中:在TC4钛合金实验中,应变率为2 000 s-1,温度范围为20～1400℃,测得其流动应力从1.6 GPa降到150MPa;在SiC实验中,应变率为250 s-1,温度范围为20～1200℃,测得其压缩强度从250 MPa降到220 MPa.根据高速摄像机记录的试样动态变形过程,分析试样的破坏模式,结果表明:在高温空气环境下,TC4钛合金试样表面有氧化层裂开现象,而在氩气环境下则没有;室温下,SiC试样初始裂纹产生时的应力为压缩强度的80％,而在1 200℃下为压缩强度的99％.
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