Cu含量对2040铝合金力学性能和耐腐蚀性能的影响

Effect of Cu content on mechanical properties and corrosion resistance of 2040 aluminum alloy

2040铝合金(Al-Cu-Mg-Ag合金)因其高强耐热特性,正取代2124和7075铝合金应用于飞机(尤其是战斗机)轮毂。用铸锭冶金法制备出不同Cu含量的2040铝合金铸锭,经均匀化退火、热轧、固溶和时效得到试验材料。用力学性能测试、SEM、TEM和电化学测试研究Cu含量对2040铝合金的力学性能和耐腐蚀性能的影响。结果表明:2040铝合金中Cu含量改变不影响时效响应速率,但峰值时效态的硬度随Cu含量的增加而增大。Cu的质量分数为4.8%的2040铝合金组织为Ω相及少量的θ'相和S相,Cu的质量分数为4.96%时,2040铝合金组织主要为Ω相,强度下降;Cu的质量分数为5.19%时2040铝合金组织中Ω相数量最多,合金的屈服强度和抗拉强度最高。Cu的质量分数为4.96%的2040铝合金自腐蚀电位为-0.61 V,自腐蚀电流密度为2.093×10^(-6)A/cm^(2),无沉淀析出带单侧宽度较小,为47 nm,耐晶间腐蚀性能最佳。

As a high⁃strength and heat⁃resistant Al⁃Cu⁃Mg⁃Ag alloy,2040 aluminum alloy is replacing 2124 and 7075 aluminum alloys for aircraft wheels abroad.The 2040 aluminum alloy ingots with different Cu contents were prepared by the ingot metallurgy method,and the experimental materials were obtained by homogenization annealing,hot rolling,solid solution and aging.Mechanical properties test,SEM,TEM and electrochemical test were used to study the effect of Cu content on the mechanical properties and corrosion resistance of 2040 aluminum alloy.The results show that the aging response rate is not affected by the change of Cu content in 2040 aluminum alloy,but the hardness value of peak aging state increases with the increase of Cu content.The microstructure of 2040 aluminum alloy with Cu mass fraction of 4.80%isΩphase and a small amount ofθ'phase and S phase.When the Cu mass fraction is 4.96%,the microstructure of 2040 aluminum alloy is mainlyΩphase,and the strength decreases.The 2040 aluminum alloy with Cu mass fraction of 5.19%has the highest yield strength and tensile strength due to the largest number ofΩphases.The self⁃corrosion potential of 2040 aluminum alloy with 4.96%Cu mass fraction is-0.61 V,the self⁃corrosion current density is 2.093×10^(-6)A/cm^(2),the width of precipitation⁃free zone is 47 nm,and the intergranular corrosion resistance is the best.