In the present work, samples of Al-Si-Cu piston alloy after T6 heat treatment were exposed for 2 h at temperatures ranging from 400 to 550 °C. The evolution of surface roughness and microstructure of the alloy during thermal exposure was studied by combination methods of roughness profiles, optical and scanning electron microscopy as well as XRD analysis. It is found that the roughness and mass of the alloy increase with the raise of the thermal exposure temperature, and the increasing rates of them are slow as the exposure temperature is below 500 °C, but accelerates abruptly when the temperature is higher than 500 °C. The variation of surface roughness of the alloy is closely related to phase transformation and oxidation during the thermal exposure.

在本工作中，将经过T6热处理的Al-Si-Cu活塞合金样品在400至550°C的温度下暴露2 h。通过粗糙度分布图，光学和扫描电子显微镜以及XRD分析相结合的方法研究了合金在热暴露过程中表面粗糙度和微观结构的演变。结果表明，合金的粗糙度和质量随热暴露温度的升高而增加，当暴露温度低于500°C时，合金的增加速率较慢，而当温度高于500°C时，其增加速率急剧增加。 C。合金表面粗糙度的变化与热暴露过程中的相变和氧化密切相关。