γ-TiAl合金的空蚀行为

Cavitation erosion of γ-TiAl alloy

利用超声振动空蚀试验设备研究了具有单相γ TiAl组织的Ti 5 0Al合金的空蚀行为 ,借助于SEM分析了其空蚀表面 ,并用洛氏硬度仪模拟空蚀过程中微射流所产生的局部载荷对Ti 5 0Al合金的作用 ,测量了其在加载过程中的变形能。结果表明 :Ti 5 0Al合金具有优异的抗空蚀性能 ,空蚀 2 6h后的累积体积损失量仅为 0 .92 6mm3 。该合金优异的抗空蚀性能归因于其在局部载荷作用下有较高的变形能和加工硬化能力。Ti 5 0Al合金的空蚀是由于晶界阻碍变形 ,造成应力集中 ,使裂纹沿晶界形成 ,导致材料沿晶剥落。

The cavitation erosion of Ti-50Al alloy with single phase γ-TiAl was investigated with an ultrasonic vibratory apparatus. The eroded surface was observed by SEM. To simulate the effect of the collapse of vapour cavities or bubbles, Rockwell hardness tester was used to exert a load on the small area of Ti-50Al. The results show that the cumulative volume loss of Ti-50Al alloy is only 0.926 mm^3 after cavitation erosion for 26 h. It has excellent cavitation erosion resistance, which is mainly ascribed to its high deformation energy and good work-hardening ability under a localized load. The cavitation erosion of Ti-50Al alloy is due to stress concentration at the grain boundaries, followed by fracture and subsequent material removal.