激光选区熔化成形原位自生TiB_2/Al-Si复合材料的微观组织和力学性能

Microstructures and mechanical properties of in-situ TiB_2/Al-Si composite fabricated by selective laser melting

利用激光选区熔化(SLM)技术制备了原位自生TiB_2纳米陶瓷颗粒增强Al-Si基复合材料,并对成形后的TiB_2/Al-Si复合材料进行不同的热处理。通过XRD物相分析、SEM微观组织观察、电子背散射衍射(EBSD)、EDS元素扫描分析和力学拉伸试验等对TiB_2/Al-Si复合材料的微观组织进行观察和力学性能测试。研究表明,在原位自生TiB_2纳米陶瓷颗粒和SLM快速凝固特性的共同作用下,SLM成形的原位自生TiB_2/Al-Si复合材料具有超细晶结构,平均晶粒尺寸为1.1μm;TiB_2/Al-Si复合材料的力学性能优异,屈服强度为262 MPa,抗拉强度为435 MPa,延伸率为11.88%。对比经不同热处理的TiB_2/Al-Si复合材料,直接时效处理(150℃/12h)的TiB_2/Al-Si复合材料性能最优,抗拉强度达到488 MPa,提高了53 MPa,延伸率降低至7.2%。

TiB2/Al-Si composite samples were produced by selective laser melting（SLM）,following by different heat treatments.The microstructures and mechanical properties of in-situ TiB2/Al-Si composites before and after different heat treatments were analyzed by XRD,SEM,electron back-scattered diffraction（EBSD）,EDS and tensile tests.The results indicate that the as-prepared SLM TiB2/Al-Si composites have ultra-fine microstructures and high mechanical properties due to the high cooling rate of SLM and the existence of nano TiB2 particles.The average grain size is 1.1μm,and TiB2/Al-Si composites show high yield strength of 262 MPa,high tensile strength of 435 MPa and excellent elongation of 11.88%.For the TiB2/Al-Si composites after different heat treatments,the mechanical properties reach its best after the direct artificial aging（150℃/12 h）.The tensile strength of the TiB2/Al-Si composites reaches 488 MPa which increases by 53 MPa,and the elongation decreases to 7.2%.