不同状态Mg-9Li-3Al-2.0Gd合金的显微组织及性能

Microstructure and Properties of Mg-9Li-3Al-2.0Gd Alloy in Different States

使用对掺法制备了铸态Mg-9Li-3Al-2.0Gd合金,之后对其进行挤压处理,研究了铸态和挤压态合金的显微组织、拉伸性能及耐腐蚀性能。结果表明:铸态合金主要由α-Mg、β-Li、Al3Gd和MgAlLi2相组成;经过挤压变形后,合金的组织得到明显细化,但其物相组成并没有发生变化,只是在挤压过程中发生了完全动态再结晶;挤压态合金的抗拉强度和伸长率分别达到了251MPa和20.2%,与铸态合金相比提高了39.4%和32%;铸态合金的拉伸断口表现为韧窝断裂与解理断裂的复合型断裂特征,而挤压态合金趋于微孔聚集型断裂;与铸态合金相比,挤压态合金表现出了更好的耐腐蚀性能。

As-cast Mg-9Li-3Al-2.0Gd alloy was prepared through mixture method,and then it was treated by means of extrusion treatment.Microstructure,tensile properties and corrosion resistance of the alloy in as-cast and as extruded states were investigated.The results exhibite that the as-cast alloy was mainly composed ofα-Mg,β-Li, Al3 Gd and MgAlLi2 phases.After extrusion process,the grains size of the alloy was refined clearly,but its phases didn’t change,only dynamic recrystallization happened during extrusion process.Tensile strength and elongation of the extruded alloy reached to 251 MPa and 20.2%,respectively,accordingly enhanced by 39.4% and 32%（compared with the alloy in as-cast state）.Tensile fracture of the as-cast alloy mainly exhibited a mixture of ductile fracture and cleavage fracture,while the extruded alloy trended to fracture with microvoid accumulation fracture characteristics.Compared with the as-cast alloy,the extruded alloy exhibited better corrosion resistance.