选区激光熔化高强铝合金TiB2/AlSi10Mg显微组织及力学性能研究

Microstructure and Mechanical Properties of Selective Laser Melting High-Strength TiB2/AlSi10Mg Parts

利用选区激光熔化技术制备了高强铝合金TiB2/AlSi10Mg试样,研究了不同的工艺参数激光体能量密度E对于成形试样的致密度、显微组织的影响规律,并用光学显微镜、扫描电子显微镜对结果进行了表征。分析了不同参数下试样的显微硬度和拉伸性能,并研究了不同的热处理制度处理后TiB2/AlSi10Mg试样拉伸性能的变化。研究发现,随着E的增加,试样上的缺陷越来越少,致密度逐渐提高,在E=71.5 J/mm3时,试样上只存在很少的缺陷,颗粒团聚现象消失且分布均匀。在该参数下,试样横截面上的显微硬度在达到了138.9 HV0.5。由于TiB2陶瓷相的加入,SLM成形铝合金的强度能够达到420 MPa,延伸率为6.13%,较SLM成形纯AlSi10Mg相比,强度提升了13.5%,延伸率提升了50%。热处理温度和热处理时间对SLM成形试验件的拉伸性能也有影响,对于本试验中,较为优化的热处理温度为T=170℃,热处理时间t=10 h。

The Selective Laser Melting(SLM)technology was utilized to fabricate high-strength TiB2/AlSi10 Mg alloy.The effects of laser energy density E on the relative density,microstructure of the as-fabricated samples were researched by means of Optical Microscope(OM)and Scan Electron Microscope(SEM).The microhardness and tensile properties of the samples at different parameters were also investigated and the effects of various heat treatment(HT)condition on tensile properties of the SLM processed TiB2/AlSi10 Mg were revealed.The results showed that the relative density of the sample improved and defects decreased with the increase of E.When E was increased to 71.5 J/mm3,there was only a few defects on sample section,and the clusters of TiB2 particles disappeared with a uniform distribution.Under this laser processing condition,the microhardness on the cross section reached to 138.9 HV0.5.Due to the addition of the TiB2 particle,the tensile property of the SLM-processed TiB2/AlSi10 Mg alloy realized a tensile strength of 420 MPa and elongation of 6.13%,showing a 13.5%and 50%increcement respectively compared with the SLM-processed pure AlSi10 Mg alloy.The temperature and time of HT also influenced the property of the TiB2/AlSi10 Mg alloy and in this research,the relative optimized HT temperature and time were T=170℃,t=10 h,respectively.