Researching Micro Structure And Properties Of Al-0.3%Si-0.5%Mg-x%B_{（x-0-0.5）} By Hot Rolling

A1 alloys have strong mechanical properties and excellent electrical conductivity to meet the growing requirements of A1 alloy of electricity transmission materials by hot rolling.The chemical composition of the A1 alloy designed by orthogonal experiment is Al-0.3%Si-0.5%Mg-xB(x=0,0.1%,0.2%,0.5%).The A1 alloys of different compositions are hot rolled after homogenizing annealing treatment(550℃ holding for 6h).The mechanical properties of the alloy materials,such as tensile strength,hardness and damping capacity and electrical conductivity were tested,and the effects and mechanism of different mass percentages of B and hot rolling processes on the mechanical properties,electrical conductivity and micro structure of A1 alloys were studied.The research shows:(1)The strengthening effect of adding B is not obvious.The optimal addition amount of B is 0.1%,Al-0.3%Si-0.5%Mg-0.1%B aluminum alloy has the best comprehensive mechanical properties,tensile strength is 137MPa,elongation rate is 19%,and hardness value is 45HV.(2)Adding B does not significantly increase the conductivity of the materials.The optimal dosage of B is 0.1%,and the highest conductivity of Al-0.3%Si-0.5%Mg-0.1%B aluminum alloy is 57.93%IACS.(3)Hot rolling can obviously improve the tensile strength,hardness and electrical conductivity of alloys.Rolling deformation can significantly change the proportion of A1 alloy internal texture.With the increase of the deformation mate of various alloys,the proportion of S texture and Brass texture are decreased,and the proportion of Cube texture and Goss texture are increased.50%rolling deformation mate can maximize the mechanical and electrical properties of the materials.The reason is that rolling changes the texture composition of the alloys,but the dynamic recrystallization grains will increase as the deformation increases,and the increase of recrystallization grains increases the resistance,so that the alloy with the largest deformation does not have the highest conductivity.(4)At room temperature,the damping properties of various A1 alloys increase with the increase of strain.The as-cast A1 alloy has the highest high strain damping property.The damping property of the hot rolled A1 alloy does not change significantly with the rolling reduction.The damping properties of various alloys increase with the increase of temperature,and the damping properties of as cast and homogenized alloys are the weakest under the variable temperature condition,except for a few damping peaks in the measured temperature range.With the increase of rolling reduction,its high temperature damping performance is higher as well.