Effect Of Room Temperature Rolling On Microstructure And Mechanical Properties Of Mg-Al-Ta Composite

In the extreme service environment represented by deep space exploration,in order to ensure the normal operation of electronic devices and other payloads,some load-bearing parts need to have the corresponding anti radiation performance.In this paper,metal tantalum with high density,metal magnesium and aluminum with low density were taken as the research objects,and the forming,microstructure and mechanical properties of Mg-Al-Ta composite metal sheet were studied by room temperature rolling,which laid the foundation for the development of new anti radiation metal structural materials.Taking AZ31B,pure tantalum and aluminum foil as experimental objects,the effects of roll rate(80-150 r/min),rolling pass(1-3),rolling reduction(20-90%)and annealing heat treatment(annealing at 300? before rolling)and high temperature heat treatment(annealing at 200? for 4h,annealing at 450? for 1h after annealing heat treatment)on magnesium based multilayer metal sheet were studied in detail OM,SEM/EDX and tensile test were used to analyze the forming,interface characteristics and mechanical properties of Mg-Al-Ta sheet.The research of room temperature rolling process shows that the roll speed has a great influence on the surface quality of sheet metal.At the low speed of 80 r/min,it is easy to get stuck and the rolling is not successful.With the increase of the rolling speed to 100 r/min,the bonding between the multi-layer metal plates becomes closer,the rolling speed continues to rise,and the surface quality of sheet metal becomes worse.With the increase of pass reduction,the interface between magnesium and aluminum shows good bonding,and the atomic diffusion width of magnesium aluminum interface increases gradually,which is 3.2 ?m,4.0 ?m,4.6 ?m,4.9 ?m,5.6 ?m,6.0 ?m in turn;the bonding of interface is greatly affected by pass preparation,and the bonding strength increases with the increase of pass The interface bonding of the sheet was improved obviously.From one pass to three passes,the atomic diffusion width of Mg-Al interface increases gradually,which is 3.2?m,4.0?pm and 4.6?m,respectively,indicating that the bonding strength increases gradually.Annealing before rolling can effectively improve the plasticity of magnesium alloy and increase the interface bonding between magnesium and aluminum.Diffusion heat treatment at 450? for 1h can effectively increase the interfacial bonding.After diffusion heat treatment,the atomic diffusion width of Mg-Al interface of rolled sheet increases from 3.2 ?m to 5.2 ?m.diffusion heat treatment promotes the diffusion of atoms at the interface of composite sheet,increases its diffusion area,and further improves the bonding strength at the interface of composite sheet.The tensile mechanical properties test results show that the tensile strength of the composite plate is 105MPa?55MPa and 37MPa respectively,and the elongation is 9.2%,0.4%and 0.6%,under 1,2 and 3 passes rolling.With the increase of passes,the tensile strength of the composite plate decreases gradually,and the elongation decreases sharply at 2 and 3 passes.Fracture analysis showed that cleavage fracture occurred in Mg and Ta layers and ductile fracture occurred in A1 layer.With the increase of passes,the plasticity of rolled sheet decreases.Through detailed analysis of the effect of room temperature rolling process on the forming of Mg-Al-Ta composite,the Mg-Al-Ta composite sheet was successfully prepared by room temperature rolling process,which laid an important foundation for the research on the functional properties of light composite metal.