Interfacial Microstructure and Mechanical Properties of Al5052/Mg-9.5Li-2Al Alloy Clad Plates

摘要:

通过冷轧制备出了Al5052/Mg-9.5Li-2Al合金复合板，研究了复合板退火后的组织与力学性能。结果表明：退火后复合板的结合界面上没有出现类似裂纹或孔洞的缺陷。经623或623 K以上的温度退火后，合金复合的界面形成反应相。Mg-9.5Li-2Al板和Al5052板之间结合界面处的主要反应相依次为α-Mg+β-Li相、Mg17Al12相、Li-dissolved Al3Mg2相和α-Al。在一定温度范围内，随退火温度的升高，界面结合强度逐渐增加。当退火温度为623 K时，复合板的结合强度达到最大值17.83 MPa，而且具有良好的塑性，延伸率达到18.7%，另外，界面未出现剥离现象。当退火温度为673 K时，覆板的拉伸性能由于界面剥离而恶化。

Abstract:

Al5052/Mg-9.5Li-2Al alloy clad plates were fabricated by cold rolling and the effect of annealing temperature on the microstructures and mechanical properties were investigated. Results show that no defects like cracks or voids are found at the bond interface in the annealed clad plates. Intermetallic layers are formed at the clad plate bond interface after annealing at and above 623 K. The main phases across the bond interface are α-Mg+b-Li, Mg17Al12, Li-dissolved Al3Mg2 and α-Al in sequence from the Mg-9.5Li-2Al base plate to Al5052 cover plate. The bond strength increases with increasing of annealing temperature below 623 K. When annealed at 623 K, the interfacial normal bond strength of the clad plates attains its maximum 17.83 MPa, with excellent ductility of an elongation of 18.7%, and no debonding is observed in the tensile specimen. When annealed at 673 K, the tensile property of the clad plates worsens due to interface debonding.