时效温度对SLM成型的AlSi7Mg微观组织与力学性能的影响

Effects of Aging Temperature on Microstructure and Mechanical Properties of AlSi7Mg Formed by SLM

使用SEM、DTA、XRD分析了激光选区熔化成型AlSi7Mg的共晶组织随时效温度升高的演化过程,对在120~280℃时效6 h的试样进行了9次拉伸实验。结果表明,微观组织的变化过程引起力学性能的变化。共晶硅组织从网状逐渐变化为颗粒状,非平衡态Mg_(2)Si相逐渐析出且向平衡态转变。低于180℃时效,网状的共晶硅组织不发生明显分解,Mg_(2)Si相弥散析出,AlSi7Mg的强度显著增加;高于180℃时效,网状共晶硅组织显著分解,材料的强度降低。在170℃时效6 h,SLM成型的AlSi7Mg的抗拉强度超过440 MPa。

The evolution of the increasing readily effective temperature of selective laser melting(SLM)formed AlSi7Mg was analyzed using SEM,DTA and XRD.Nine tensile experiments were performed on the samples at 120-280℃aging for6 h.The results show that the changes of process of microstructure causes changes in mechanical properties.Coocrcrystalline silicon microstructure gradually changes from mesh to granular,non-equilibrium Mg_(2)Si phase gradually emerges and shifts to the equilibrium state.Under 180℃aging,mesh crystalline silicon microstructure does not generate significant decomposition,Mg_(2)Si phase dispersion separates out,the strength of Al Si7Mg significantly increases.Below 180℃aging,mesh crystalline silicon microstructure is significantly decomposed and the strength of the material decreases.After aging process at 170℃for 6h,the tensile strength of SLM AlSi7Mg exceeds 440 MPa.