采用选区激光熔化(SLM)技术制备了CoCrMo合金。研究了激光线能量密度对SLM成型试样过程中飞溅行为的影响。在合理激光线能量密度区间,采用不同的激光能量和扫描速度进行块体成型试验,以高度方向尺寸精度为标准,选择最优工艺参数。在尺寸精度最高的前提下,研究了SLM成型CoCrMo合金试样的显微组织和力学性能。通过热处理工艺提高了试样的机械性能。研究结果表明,在激光线能量密度0.21 J/mm,激光功率115 W,扫描速度550 mm/s时,成型试样尺寸精确度可以达到0.03 mm。成型试样表面光滑,粗糙度Ra为6.149 μm,致密度可达99.7%,近乎全致密。在细晶强化作用下,成型试样的抗拉强度为1 057 MPa,延伸率为6.7%; T4热处理后,在固溶强化作用下,抗拉强度提升至1 153 MPa,延伸率提升至17.8%。

CoCrMo alloy was prepared by selective laser melting (SLM) technology. The effect of laser line energy density on the spatter behavior during SLM forming specimens was studied. In the reasonable laser line energy density interval, the block forming test was performed with different laser energy and scanning speeds, and the optimal process parameters were selected according to the height direction dimensional accuracy. Under the premise of the highest dimensional accuracy, the microstructure and mechanical properties of the SLM formed CoCrMo alloy specimens were studied. The mechanical properties of the specimen were improved by a heat treatment process. The results show that the dimensional accuracy of the molded specimen can reach 0.03 mm when the laser line energy density is 0.21 J/mm, the laser power is 115 W, and the scanning speed is 550 mm/s. The surface of the molded specimen is smooth, the roughness Ra is 6.149 μm, the density is up to 99.7%, and it is almost full density. Under the action of fine grain strengthening, the tensile strength of the molded specimen is 1 057 MPa and the elongation is 6.7%. After the heat treatment of T4, the tensile strength is increased to 1 153 MPa and the elongation is increased to 17.8% under solid solution strengthening.