成形角度对选区激光熔化4Cr5MoSiV1钢组织和性能的影响EI北大核心CSCD

选区激光熔化(SLM)成形4Cr5MoSiV1钢具有良好的强/硬度以及耐磨性是提高其使用寿命的重要保证,为优化SLM成形4Cr5MoSiV1钢的组织和性能,研究不同成形角度下4Cr5MoSiV1钢试样的显微组织、显微硬度、拉伸性能和耐磨性。结果表明:随成形角度的增加,试样熔道间的热量累积程度降低,晶粒尺寸减小,细晶强化作用增强,故试样的显微硬度升高。随成形角度的增加,拉伸试样的滑移搭接面数量增多,滑移程度增加,且熔道边界处分正应力值降低,故试样的抗拉强度和断裂伸长率均升高。磨损试样的磨损机制以黏着磨损和氧化磨损为主,且随成形角度增加,试样的耐磨性升高。同一成形角度下,试样底层表面经多次热量累积后,其细晶强化和固溶强化作用减弱,显微硬度和耐磨性均降低。SLM成形4Cr5MoSiV1钢试样的显微硬度、耐磨性和拉伸性能呈正相关,45°成形角度下试样的力学性能最高,抗拉强度最高为1576.5 MPa,断裂伸长率最高为17%,顶层表面的显微硬度最高为608.4HV,顶层表面的磨损率最低为4.95×10^(-9)kg·N^(-1)·m^(-1)。

Effect of forming angle on microstructure and properties of 4Cr5M oSiV1 steel formed by selective laser melting

Selective laser melting(SLM) 4Cr5MoSiV1 steel has good strength/hardness and wear resistance, which is the important guarantee to improve its service life. In order to optimize the structure and properties of 4Cr5MoSiV1 steel formed by selective laser melting, the microstructure, microhardness, tensile properties and wear resistance of 4Cr5MoSiV1 steel samples were studied under the different forming angles. The results show that with the increase of forming angle, the heat accumulation between the melt channels of sample is decreased, the grain size is decreased, and the fine grain strengthening is enhanced, so the microhardness of the sample is increased. With the increase of forming angle, the number of slip lap surfaces and the degree of slip of tensile sample are increased, and the normal stress at the melt boundary is decreased, so the tensile strength and elongation after fracture of the sample are increased. The wear mechanisms of the wear sample are mainly adhesive wear and oxidation wear, and the wear resistance of the sample is increased with the increase of forming angle. At the same forming angle, after repeated heat accumulation on the surface of the sample bottom layer, the fine grain strengthening and solid solution strengthening are weakened, and the microhardness and wear resistance are reduced, so the microhardness and wear resistance of the sample are decreased. The microhardness, wear resistance and tensile properties of 4Cr5MoSiV1 steel sample formed by SLM are positively correlated. The mechanical properties of sample are the highest at 45° forming angle, the highest tensile strength is 1576.5 MPa, the highest elongation is 17%, the highest micro-hardness of upper surface is 608.4HV, and the lowest wear resistance of the upper surface is 4.95×10^-9 kg·N^-1·m^-1.