SiC含量对激光选区熔化制备SiC_(P)/AlSi10Mg复合材料组织与性能的影响

Effects of SiC Content on Microstructure and Properties of SiC_(P)/AlSi10Mg Composites Prepared by Selective Laser Melting

采用激光选区熔化(SLM)成形技术分别制备了SiC颗粒含量15wt%、30wt%的SiC_(P)/AlSi10Mg复合材料。研究了SLM工艺参数扫描速度对不同SiC颗粒含量的复合材料致密度、显微组织、显微硬度的影响规律。结果表明,随着激光扫描速度的升高,两种复合材料的致密度、显微硬度均降低。同一工艺参数下,随SiC颗粒含量升高,基体中出现大量孔洞、裂纹、未熔颗粒等缺陷,导致致密度降低。激光功率490 W、铺粉层厚0.04 mm、扫描间距0.12 mm、扫描速度1000 mm/s的工艺参数下,SiC颗粒含量15wt%时,可达到最大相对密度96.2%,而增加SiC颗粒含量至30wt%,最大相对密度仅为90.2%。随着SiC颗粒含量的增加,基体中位错密度升高,导致显微硬度增大,最大显微硬度可达228.5HV0.2,与SLM成形的未添加SiC颗粒AlSi10Mg显微硬度相比有明显升高。

The SiC_(P)/AlSi10Mg composites with SiC particle content of 15 wt%and 30 wt%were prepared by laser selective melting(SLM)forming technique.The effects of SLM process parameter of scanning speed on the density,microstructure and microhardness of the composites with different SiC particle content were studied.The results show that,the density and microhardness of the two composites decrease with the increase of laser scanning speed.Under the same process parameters,with the increase of SiC particle content,a large number of holes,cracks and unmelted particles appear in the matrix,which leads to the decrease of density.When the laser power is 490 W,the powder thickness is 0.04 mm,the scanning distance is 0.12 mm,and the scanning speed is 1000 mm/s,the maximum relative density of 96.2%can be obtained when the content of SiC particles is 15 wt%.The maximum relative density is 90.2%when the content of SiC particles is increased to 30 wt%.With the increase of SiC particle content,the dislocation density in the matrix increases,which results in the increase of microhardness,the maximum microhardness of which can reach 228.5 HV0.2.Compared with the microhardnessof AlSi10Mg without SiC particles formed by SLM,the microhardness is obviously increased.