Mg-13Gd-1Zn合金的组织与力学性能

研究了铸态、退火态、挤压态和T5时效态Mg-13Gd-1Zn三元合金的显微组织和力学性能。结果表明，合金的铸态组织由α-Mg、(Mg,Zn)₃Gd和14H-LPSO长周期相组成。合金在均匀化退火和热挤压后的直接时效(T5)过程中都发生了晶内14H-LPSO相的沉淀析出，表明合金中14H-LPSO的沉淀相变发生在一个很宽的温度范围(200~510℃)。在挤压后合金的直接时效(T5)过程中发生了β'及β₁相的沉淀析出。在沉淀强化和LPSO强化的共同作用下，合金的屈服强度、抗拉强度和伸长率分别为197 MPa、397 MPa和2.56%。在200℃/80 MPa和200℃/120 MPa两种实验条件下，Mg-13Gd-1Zn合金的抗蠕变性能均优于WE54合金。

Microstructures and Mechanical Properties of Mg-13Gd-1Zn Alloy

A ternary alloy with composition of Mg-13Gd-1Zn (%, mass fraction) was prepared by conventional smelting and casting technique. The microstructure and mechanical properties of the as-cast, as-annealed, as-extruded and as-aged (T5) alloy were investigated. The results show that the microstructure of the as-cast alloy consists of α-Mg matrix, (Mg, Zn)₃Gd eutectic and a 14H long period staking ordered (14H-LPSO) phase. The significant increase of 14H-LPSO phase after annealing and ageing (T5) treatment in the alloy microstructure indicates that the precipitation of the 14H-LPSO phase occurs in a wide temperature range (200~510^oC). The β' and β₁ precipitates have also been observed in the alloy after ageing (T5) treatment. Under the combined action of precipitation strengthening and LPSO strengthening, the tensile strength, yield strength and elongation of the alloy are 397 MPa, 197 MPa and 2.56%, respectively. The creep properties of the Mg-13Gd-1Zn alloy are higher than those of the WE54 alloy in the two experimental conditions of 200^oC/80 MPa and 200^oC/120 MPa.