激光冲击对中高温服役条件下镍基合金K417显微硬度的影响

Effects of Laser Shock Processing on Micro-Hardness of Ni-Based Superalloy K417 at Elevated Temperature

为研究中高温环境下的激光冲击强化效果,采用功率密度8.5GW/cm2、脉冲宽度10ns的强激光对K417镍基合金冲击改性,利用维氏硬度法测试其在700℃、800℃、900℃保温后的显微硬度值。结果表明中高温保温后,激光冲击硬化效果有所减弱,但不同温度下激光冲击区域的平均硬度均明显大于未冲击区域;深度方向硬度近似呈指数形式衰减,硬化层深度随温度的增加呈减小趋势;单个光斑径向硬度分布与激光空间分布特性导致的等离子体冲击波不均匀相关。研究表明在800℃以下,激光冲击有效提高了K417的综合性能指标。

In order to study the effect of laser shock processing （LSP） in high temperature environment, the K417 superalloy is treated by LSP with laser power density of 8.5 GW/cm： and pulse width of 10 ns, and then the Vikers hardness of K417 is tested after heat treatment at 700° C , 800 °C and 900 °C , respectively. The results show that the hardening effect is weakened at elevated temperature, but the average hardness of LSP region is obviously higher than that of non-LSP region. With the temperature increasing, the thickness of the LSP hardened layer shows a decreasing trend and the hardness in the depth direction is fitted with exponential function approximately. The hardness distribution on a single laser spot is related to the laser shock wave＇s inequality which is induced by the laser spatial distribution. The research indicates that LSP can raise the K417 superalloy＇s comprehensive properties under 800°C.