Microstructural evolution and mechanical properties of an ultrahighstrength Al-Zn-Mg-Cu alloy via powder metallurgy and hot extrusion

In this work,a novel ultrahigh-strength Al-10Zn-3.5Mg-1.5Cu alloy was fabricated by powder metallurgy followed by hot extrusion.Investigations on microstructural evolution and mechanical properties of the fabricated samples were carried out.The results show that the grain size of sintered samples matches with the powder particles after ball milling.The relative densities of sintered and hot extruded samples reach 99.1%and 100%,respectively.Owing to the comprehensive mechanism of grain refinement,aging and dispersion strengthening,the ultimate tensile strength,yield strength and elongation of the Al-10Zn-3.5Mg-1.5Cu alloy after hot extrusion and subsequent heat treatment achieve 810 MPa,770 MPa and 8%,respectively.

AZ31B镁合金表面激光合金化Al-Cu涂层制备及其性能研究

针对镁合金表面耐磨性差的问题,采用预置粉末法对AZ31B镁合金表面进行激光合金化Al-Cu粉末试验。通过扫描电子显微镜(SEM)、X射线衍射(XRD)仪、显微硬度计、摩擦磨损试验机对合金化涂层的相组成、微结构及性能进行了分析。结果表明,涂层与基体呈冶金结合、组织均匀致密、呈网状结构;涂层中除了有α-Mg、β-Al12Mg17外还含有CuMg2,且β-Al12Mg17含量远高于基体材料;涂层的显微硬度由50HV提高到210～265HV,为基体的4～5倍,相对耐磨性为2.5。