不同应变率下蓝宝石透明陶瓷玻璃的力学响应

蓝宝石（A1₂O₃）是透明陶瓷玻璃，它相较传统陶瓷（A1₂O₃）有优良的透光性，而且保留了陶瓷优良的力学性能。利用电子拉伸机和分离式霍普金森杆设备对试样进行准静态应变率为(10?4、10?3、10?2 s?1)和4种动态应变率(850、1 100、1 300、1 450 s?1)下的单轴压缩力学行为，用高速摄像机记录了蓝宝石透明陶瓷玻璃试样在准静态和动态压缩下的破坏过程。实验结果表明:从加载过程中的应力应变曲线是由加载段和失效段组成的，该材料是典型的脆性材料，并且有明显的应变率效应，随着应变率的提高，蓝宝石透明陶瓷玻璃的抗压强度也会提高；准静态和动态压缩下蓝宝石透明陶瓷玻璃都是在宏观裂纹扩展作用下失效破坏。通过分析不同应变率下蓝宝石透明陶瓷玻璃的破坏过程，分析得到该材料的失效是在加载的过程中，在蓝宝石透明陶瓷玻璃承载能力最低的区域出现裂纹源，然后裂纹成形并沿着加载方向扩展，然后裂纹之间相互交错，最终达到饱和状态破坏失效；在高应变率下，极短的时间内产生多处裂纹源，需要更大的能量去使裂纹成形、扩展，宏观上就表现为应变率效应。

Mechanical response of sapphire transparent ceramic glass at different strain rates

Sapphire (Al₂O₃) transparent ceramic glass has excellent light transmittance and retains the excellent mechanical properties comparing with traditional ceramics. In order to understand the relationship between strength and strain rate of sapphire transparent ceramic glass and its failure process, the electronic tensile machine and split Hopkinson bar equipment were used to load the specimen at different strain rates (10?4, 10?3, 10?2, 850, 1 100, 1 300, 1 450 s?1). The quasi-static and dynamic compression failure processes of specimen were recorded by high-speed camera. The experimental results show sapphire transparent ceramic glass is a typical brittle material with strain rate effect. With the increase of strain rate, the compressive strength of the sapphire transparent ceramic glass will also increase. The failure cycle of sapphire is long under quasi-static compression, and the crack will expand along the path with the weakest bearing capacity. In addition, the strength curve of sapphire will decline briefly and then continue to rise, which is caused by the increase and propagation of the number of cracks. In the process of dynamic compression, the sapphire reaches the cracking strength in many places, forming more crack sources, and then the crack forms and expands to split the sapphire. When the sapphire transparent ceramic glass is subjected to compression, cracks will appear in the region with the weakest bearing capacity in the process of loading; soon after the cracks take shape and expand along the loading direction, the cracks interlace to reach a saturation state; and finally reach the compressive strength failure. Under dynamic compression, however, due to the loading rate is much higher than the propagation of the crack, several crack sources appear in the sapphirine transparent ceramic glass within a very short period of time, which requires more energy to make the crack forming and extending, exhibiting as the strain rate effect on its macro-scale performance.