Preparation And Mechanical Characteristics Of Al/Mg Non-equilibrium Alloys

Al/Mg non-equilibrium alloys were fabricated by Rotational Friction Extrusion(RFE)with 5A06 aluminum alloy and AZ31B magnesium alloy were used as substrates.The metal flow characterwastics and alloy surface forming during the preparation of Al/Mg alloys was studied,The orientation imaging,grain size dwastribution,grain boundaries,orientation difference dwastribution and texture of Al/Mg alloys were measured by EBSD technique,and the hardness,tensile strength and elongation of non-equilibrium alloys were tested.The fracture morphology of non-equilibrium alloys were observed.The change of microstructure and the mechanical characterwastic of Al/Mg alloys with different magnesium content were investigated.The results show that the extrusion process of Al/Mg non-equilibrium alloys was divided into three stages that was extrusion stage,stirring stage and forming stage.The phenomenon of“peeling”appeared on the surface of the prepared Al/Mg non-equilibrium alloy.With the increase of magnesium content,The phenomenon of“peeling”on non-equilibrium alloy became more and more serious.The phenomenon of“peeling”on the surface of 10vol%Al/Mg non-equilibrium alloys was the most serious.The Al/Mg non-equilibrium alloys was composed of?(Al)and Al₃Mg₂ phases,and the band structure of?(Al)+Al₃Mg₂ was observed in the alloy.The Al/Mg non-equilibrium alloys prepared by RFE had a relatively uniform structure,the alloy undergoes dynamic recrystallization during the preparation process,and the structure was fine equiaxed grains.As the magnesium content increasing,the grain size of the non-equilibrium alloy decreased,and the average grain size of the 10vol%Mg Al/Mg non-equilibrium alloys was the smallest,5?m;the average grain size of the aluminum substrate decreased 78.6%.The main grain orientation of the aluminum substrate was<001>crystal orientation and<101>crystal orientation,containing a small amount of<111>crystal orientation;after RFE processing,the<111>crystal orientation and<001>crystal orientation in the substrate increased,but the<101>crystal orientation decreased.In Al/Mg non-equilibrium alloys,<101>to<111>crystal orientation and<001>crystal orientation transformation occurred,and the 10%by volume Al/Mg non-equilibrium alloys<111>had the most crystal orientation content,<001>crystal orientation and<101>>The crystal content was equivalent.The KAM value of the aluminum substrate is evenly distributed and is distributed between 0?0.5°.The KAM value inside and near the boundary of some grains wad between 1°?1.5°.After RFE processing,the KAM value wad between 1°?1.5°.The number of grains and grain boundaries increased,and the local orientation difference curve of the 5%vol Mg Al/Mg non-equilibrium alloys shifted to a larger value,and there were more grains and grain boundaries with orientation differences between 1°and 1.5°.The ratio of HAGBs in the Al/Mg non-equilibrium alloys was higher than that of the original base material.The HAGBs ratio of 10vol%Mg Al/Mg non-equilibrium alloys reached85.7%,which was an increasing of 47.3%compared to the base material.The average orientation difference was 45.7%,which was about 2 times the wood.The maximum polar density and maximum orientation function of the 10vol%Mg Al/Mg non-equilibrium alloys was the lowest,which was 1.91 and 1.97,respectively.The hardness and tensile strength of the Al/Mg non-equilibrium alloys was improved compared with the substrate.With the increasing of magnesium content,the hardness and tensile strength of the Al/Mg non-equilibrium alloys gradually increased,and the elongation increased first and then gradually decreased.10vol%Mg Al/Mg non-equilibrium alloys had the largest hardness value of 137.1HV,an increasing of56.7%compared to the substrate;the largest tensile strength was 332.6 Mpa,an increasing of 74%compared to the substrate;the elongation was the smallest,1.1%.The fracture method of aluminum substrate was microporous polymerization fracture,the fracture method of Al/Mg non-equilibrium alloy was a tough and brittle mixed fracture with both microporous polymerization fracture and cleavage fracture.Crystal strengthening and dislocation strengthening.