高强韧镁合金大规格型材挤压成形的数值模拟及实验研究

Numerical simulation and experimental study on extrusion forming of high strength tough magnesium alloy large size profiles

摘要:

大规格镁合金型材在轨道交通等领域的需求及要求都日益增加，大规格高强韧镁合金型材在常规技术下制备时，试模成本高，研发周期长，难度极大。本文利用HyperXtrude软件对大规格高强韧Mg-9Gd-4Y-1Zn-0.8Mn合金轨道交通用支撑梁型材进行了型材结构优化前后的数值模拟，在保证大规格高强韧镁合金支撑梁型材能成功挤压成形的前提下，确定出了优选工艺，即挤压温度470 ℃，挤压速度0.3 mm/s，该工艺下所需最大挤压力为34606 KN。成功制备出了表面质量良好、成分均匀、组织均质的轨道交通用大规格高强韧镁合金支撑梁型材。型材各区域的抗拉强度都在370 MPa以上，延伸率在10%以上，最高强度达到391 MPa；时效态的强度提高明显，达到460 MPa以上，延伸率略微下降，超过8%，最高强度达到475MPa。

Abstract:

The demand and requirements of large-size magnesium alloy profiles in the field of rail transit and other fields are increasing. The high strength tough magnesium alloy profiles have high trial mold cost, long development cycle and difficult preparation. In this paper, the HyperXtrude software is used to simulate the profile structure of the large-size high-strength and tough Mg-9Gd-4Y-1Zn-0.8Mn alloy rail transit support beam. Under the premise of ensuring the successful extrusion of large-size high-strength and tough magnesium alloy support beam profiles, the preferred process is determined. The extrusion temperature is 470 ℃, the extrusion speed is 0.3 mm/s, and the maximum pressing force required under the process is determined which is 34606 KN. The large-size high-strength and tough magnesium alloy support beam profile used in rail transit with good surface quality, uniform composition and homogeneous structure is successfully prepared. The tensile strength of each part of the profile is above 370 MPa, the elongation is above 10%, and the highest strength is 391 MPa. The strength of the aging state is obviously improved, reaching 460 MPa or more, and the elongation is slightly decreased, exceeding 8%. The highest strength reaches 475 MPa.