激光选区熔化成形TiB2与SiC颗粒混杂增强铝基复合材料的显微组织与力学性能

Microstructures and mechanical properties of aluminum matrix composites reinforced with hybrid TiB2 and SiC prepared by selective laser melting

在AlSi10Mg合金雾化粉末中添加2%纳米TiB2颗粒和1%亚微米SiC颗粒(均为质量分数),通过低能球磨制备(TiB2+SiC)/AlSi10Mg复合粉末,并采用激光选区熔化(SLM)技术制备(TiB2+SiC)/AlSi10Mg复合材料。采用X射线衍射(XRD)、背散射电子衍射(EBSD)、扫描电镜(SEM)等手段对比研究(TiB2+SiC)/AlSi10Mg复合材料和AlSi10Mg合金的显微组织,并测定材料的拉伸性能。结果表明,(TiB2+SiC)/AlSi10Mg复合粉末的激光反射率低于AlSi10Mg合金粉末的激光反射率(分别为31%和46%),可在较低激光功率(240 W)下进行激光选区熔化成形制备性能优良的(TiB2+SiC)/AlSi10Mg复合材料。TiB2和SiC陶瓷增强颗粒均匀分布,无明显团聚,少量TiB2聚集长大至微米级。通过用(TiB2+SiC)颗粒混杂增强,AlSi10Mg合金的平均晶粒尺寸从7.88μm减小至2.48μm,晶粒组织由粗大柱状晶转变为细小等轴晶及少量短棒状晶,抗拉强度由453.1 MPa提高至509.8 MPa,伸长率从7.2%提高至10.6%。

The(TiB2+SiC)/AlSi10Mg composite powders,with 2%nano-TiB2 particles and 1%submicron-SiC particles were prepared by low-energy ball milling and used for selective laser melting(SLM)process.The microstructures and mechanical properties of aluminum matrix composites(AMCs)reinforced with hybrid TiB2 and SiC and AlSi10Mg alloy were studied by XRD,EBSD and SEM.The results show that the laser reflectivity of the composite powders reduces from 46%to 31%compared to that of AlSi10Mg alloy powders.AMCs reinforced with TiB2 and SiC,with excellent properties,were successfully prepared by SLM at a low laser power of 240 W.Nano-TiB2 particles and submicron-SiC particles are uniformly distributed inside the grains,but a few nano-TiB2 particle sagglomerate and growup tomicron-scale.With the addition of nano-TiB2 particles and submicron-SiC particles,the coarse columnar grains are transformed into equiaxed grains and the average grain size decreases from 7.88μm to 2.48μm.The tensile strength,ductility increase to 509.8 MPa,10.6%,respectively.