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利用选区激光熔化(SLM)工艺成功制备了TiC增强Ti基纳米复合块体材料,其中TiC质量分数为30%。研究了激光线能量密度η(激光功率与扫描速率之比)对SLM成形试件的表面形貌、致密度、微观组织及力学性能的影响。结果表明,在η=400 J/m时,SLM成形试件表面较为光滑,成形致密度达到95.5%,平均显微硬度为750 HV,增强体TiC以细小层片状纳米结构均匀分布于Ti基体中。摩擦磨损试验表明,激光成形复合材料的摩擦系数为0.2,远低于SLM纯钛成形件(摩擦系数为1.2)。在较高激光线能量密度下(800 J/m),因热裂纹产生和增强体TiC枝晶粗化,致使复合材料致密度、显微硬度及磨损性能下降。
TiC reinforced Ti-based nanocomposites were successfully prepared by the selective laser melting (SLM) process, in which TiC mass fraction was 30%. The effects of laser line energy density η (ratio of laser power to scan rate) on surface morphology, density, microstructure and mechanical properties of SLM formed specimens were investigated. The results show that at η = 400 J / m, the surface of SLM is smooth, the density of forming is up to 95.5% and the average microhardness is 750 HV. The strengthening TiC is uniformly distributed on the Ti matrix with the fine lamellar nanostructures in. Friction and wear tests show that the friction coefficient of laser-formed composites is 0.2, much lower than that of SLM pure titanium forming parts (the friction coefficient is 1.2). At higher laser energy densities (800 J / m), the densification, microhardness and wear resistance of the composites decrease due to the generation of hot cracks and the dendrite coarsening of TiC.