热锻对5A06-T6挤压态铝合金力学性能和组织的影响

Influence of hot forging on mechanical properties and microstructure for 5A06-T6 extruded aluminum alloy

利用力学实验机、OM、SEM、TEM等测试手段,分析热锻处理对喷射成形5A06-T6挤压态铝合金显微组织与力学性能的影响。研究结果表明:热锻后5A06-T6挤压态铝合金基体中的晶粒发生明显细化,形成致密结构,同时相邻晶粒的孔隙数量明显减少,合金中生成了许多尺寸不同的晶粒。合金热锻后黑色析出相发生明显聚集,在组织中未产生孔隙结构。对热挤压与热锻试样进行T6峰值时效处理后,没有出现显著的PFZ现象,热锻合金的拉伸强度、屈服强度略有下降,伸长率、硬度和电导率略有增加。在热锻合金断口区域形成比挤压合金更多的韧窝,这些韧窝基本分布于撕裂棱的间隙中,且合金撕裂棱数量显著增加。

The influence of hot forging treatment on microstructure and mechanical properties of 5A06-T6 extruded aluminum alloy were analyzed by mechanical testing machine,OM,SEM and TEM.The results show that the grains in the 5A06-T6 extruded aluminum alloy after hot forging are obviously refined to form dense structure.Meanwhile,the number of pores in adjacent grains is significantly reduced,and many grains of different sizes are generated in the alloy.After the hot forging of alloy,the black precipitated phase has obvious aggregation, and there is no pore structure in the microstructure.After hot extrusion and hot forging samples are subjected to T6 peak aging treatment,no significant PFZ phenomenon occurs.However,the tensile strength and yield strength decrease slightly,and the elongation,hardness and conduetivity of hot-forging alloy increase slightly.Furthermore,more dimples are formed in the fracture area of hot-forged alloy than that of extruded alloy,and these dimples are basically distributed in the gap between tearing edges,and the number of tearing edges of alloy increases signifi- cantly.