科研之友
微信
新浪微博
Facebook
分享链接
摘要
The Al-Mg-Si and Al-Mg-Si-Mn alloy strips with fine grains and homogeneous microstructure were prepared by the single roll melt rotating process, and the strip was prefabricated and hot extruded into densified bar at 500 ℃, and then it was treated by solid solution and artificial ageing treatment. The results reveal that the strip produced by the melt-spun method presents uniform structure with fine grain,and the tensile strength and yield strength of Al-Mg-Si-0.2Si alloy reach 227 MPa and 160 MPa, greatly increased compared with those of the Al-Mg-Si alloy, respectively, while the elongation remains above 20%. The addition of Mn can promote the formation of a new second phase MnAl6, which is nailed to the grain boundary, hindering the migration of subcrystals during the extrusion process, and thus inhibiting the dynamic recrystallization. In addition, certain amount of Fe in β-AlFeSi phases are replaced by Mn to form β-Al(FeMn)Si, resulting in the long-needle shape β phase transforming into lumpy α-Al8(FeMn)2Si phase, relieving the harmful effects of Fe. At T6 state, Mn-containing dispersed phase formed in Al-Mg-Si-Mn alloy can inhibit the transition from small angle grain boundary to large angle grain boundary. In addition, new grain orientation and texture deflection occurr in both alloys, however <111> texture still is remained in Al-Mg-Si-Mn alloy, which may be attributed to the inhibition of sub-grain boundary migration by Mn-containing dispersed phase in original deformed texture during recrystallization, hindering the growth of recrystallized grains. Compared with Al-Mg-Si alloy, the Al-Mg-Si-Mn alloy is preferred to maintain its original orientation under heat treatment.
- 单位
