时效处理对AlSi9Cu3压铸铝合金组织和力学性能的影响

Effect of aging treatment on microstructure and mechanical properties of AlSi9Cu3 HPDC aluminum alloy

通过拉伸试验、光学显微镜、扫描电镜及能谱仪等分析手段研究了T5时效处理(160℃×6 h)后AlSi9Cu3高压铸造(HPDC)铝合金的显微组织、力学性能和拉伸断口形貌。结果表明,AlSi9Cu3高压铸造铝合金试样经过时效处理后,显微组织主要为等轴晶状的初生α-Al、共晶Si相以及析出θ-Al_(2)Cu相和α-Fe相。析出的平衡相θ-Al_(2)Cu弥散分布在晶界上,提高了AlSi9Cu3压铸铝合金的强度和硬度。时效处理后,AlSi9Cu3压铸铝合金的抗拉强度、屈服强度、伸长率和硬度分别为375 MPa、258 MPa、4.0%和94 HBW。同时在AlSi9Cu3压铸铝合金的拉伸断口观察到了准解理和少量沿晶断裂特征。

Effect of aging treatment(T5 treatment,160℃for 6 h)on microstructure,mechanical properties and tensile fracture morphology of AlSi9 Cu3 HPDC aluminum alloy was studied by means of tensile test,optical microscope(OM),scanning electric microscope(SEM)and energy disperse spectroscopy(EDS)analysis.The results indicate that microstructure of the aged AlSi9 Cu3 HPDC alloy is composed of equiaxed primaryα-Al,eutectic Si and precipitated phase ofθ-Al_(2)Cu andα-Fe.The precipitated phaseθ-Al_(2)Cu is observed on the grain boundary,which results in significant increase of tensile strength and hardness of the AlSi9 Cu3 alloy.After aging,the tensile strength,yield strength,elongation and hardness of the AlSi9 Cu3 alloy can reach 375 MPa,258 MPa,4.0%and 94 HBW,respectively.Meanwhile,the quasi cleavage fracture and a small amount of intergranular fracture are observed at tensile fracture of the AlSi9 Cu3 alloy.