激光辐照超音速气流下TA15钛合金和LY12铝合金的热响应

Thermal response of TA15 titanium alloy and LY12 Aluminium alloy irradiated by laser under supersonic tangential flow

利用超音速气流环境模拟装置,开展了自然对流和马赫数为3切向气流下,1064nm连续激光辐照TA15钛合金和LY12铝合金热响应实验研究,得到了材料在两种条件下的温升曲线及熔穿时间。结果表明:在激光辐照材料未使得其表面发生熔化前,气流对材料激光辐照过程中的冷却效应较为明显,在表面发生熔化时,熔化的液态物质在气流切向力剥蚀作用下被吹离材料表面,使得激光继续作用在材料上,熔化→剥离→熔化→剥离如此反复,可加速熔穿过程;此外,切向气流将影响钛合金这类热扩散系数较低材料的温度场分布,使得气流下游处的温度高于上游,而对铝合金这类热扩散系数较高的材料而言,影响不明显。

The thermal response experiments of TA15 Ti alloy and LY12 A1 alloy irradiated by CW laser in supersonic flow or natural convection conditions were done, temperature history curves and perforation time were obtained. The results show that the flow effect is cooling before the material is melted, it is denudation effect while the material is melting, it is helpful of acceler- ating the material ablation and perforation. The tangential air flow can have an effect on the temperature distribution of TA15 Ti alloy, but no effect on A1 alloy.