为改善AZ91D镁合金的表面性能,采用预置粉末脉冲激光熔覆法在镁合金表面制备钴基合金涂层,用扫描电镜(SEM)和能谱仪(EDS)分析熔覆层与基体结合界面特征、熔覆层成分.并结合Co-Cr相图、Co-W-C相图分析了熔覆层的组织形成过程,对基体及熔覆层显微硬度和耐蚀性进行测试.结果表明:合金层与基体冶金结合,熔覆层无明显缺陷;熔覆层硬度约为560 HV达到基体的9倍；钻基合金层的耐蚀性能较高,自腐蚀电位比AZ91D镁合金基体提高1.18 V,腐蚀电流降低约5个数量级.

The effect of focusing geometry on slope of carrier–envelope (CE) phase ϕCE versus propagation distance from the focus in few-cycle laser pulses is investigated. The slope could be adjusted by changing the distance L between the waist of the incident beam and the lens. At the focus, ∂ϕCE/∂(z/zR) = 0 when L = 0, and ∂ϕCE/∂(z/zR) = −2 when L = ∞. The longer the distance L, the steeper the curve of the CE phase at the focus.