6201铝合金管材半固态连续扩展成形实验研究

采用半固态连续扩展成形技术,成功地试制了扩展比为3 52的6201铝合金管材·对其微观组织和力学性能的变化及机理进行了研究·实验表明:出模温度超过510℃时,其组织发生完全再结晶;T6,TA状态半固态连续扩展成形管材的强度随着时效时间的增加呈明显的上升趋势,而延伸率则呈明显的下降趋势·扩展成形工艺的关键在于确保成形终了温度高于520℃,T6状态的管材抗拉强度为299MPa,延伸率为9 4%;TA状态的管材抗拉强度为258MPa,延伸率为12 4%;力学性能演化机理分析表明,采用合适的连续扩展成形工艺与时效处理工艺能保证获得拉伸强度和延伸率匹配最佳的6201母线管材·

Experimental Study on Continuous Semi-Solid Expansion Forming Process of 6201 Al-Alloy Tubes

The 6201 Al-alloy tubes were produced successfully through semi-solid continuous expansion forming process with an extrusion ratio 3.52. The microstructure, mechanism and change of mechanical properties were studied under T6 and TA heat-treatment processes. The results indicate that the microstructure of tubes is fully recrystallized when the demoulding temperature exceeds 520°C, and the tube strength after semi-solid continuous expansion forming process and under T6 and TA heat-treatments increases obviously with the increase of aging time, but the elongation tends to decrease obviously. The key points to the expansion forming process are to make sure that the demoulding temperature should be over 520°C, and the tensile strength of tube up to 299 MPa in T6 state with the elongation 9.4%, as well as 258 MPa with 12.4% in TA state. An evolution mechanism analysis of mechanical properties shows that the conduit tubes made from 6201 Al-alloy for bus bars with an optimum combination of tensile strength and elongation can be obtained by choosing proper continuous expansion forming process and aging treatment.