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利用拉伸试验,光学金相,X射线物相分析,SEM及TEM等试验方法,研究了加0.2%Sc和0.4%Sc(质量分数)对7055铝合金组织与高温力学性能的影响。实验结果表明:添加微量Sc元素能有效细化合金铸态组织(晶粒尺寸维持在40μm左右),抑制合金再结晶,提高合金的再结晶温度到450℃以上,形成均匀弥散分布的Al3(Sc,Zr)粒子,显著提高了合金的常温力学性能,同时一定程度上改善了其在100～200℃范围内的合金塑性和拉伸强度。
The effects of addition of 0.2% Sc and 0.4% Sc (mass fraction) on the microstructure and mechanical properties of 7055 aluminum alloy were studied by means of tensile test, optical metallography, X-ray phase analysis, SEM and TEM. The experimental results show that adding trace amount of Sc can effectively refine the as-cast microstructure of the alloy (the grain size is maintained at about 40μm), inhibit the recrystallization of the alloy and raise the recrystallization temperature of the alloy to above 450 ℃, forming uniformly dispersed Al3 (Sc , Zr) particles significantly improve the mechanical properties of the alloy at room temperature, and to some extent, improve its plasticity and tensile strength in the range of 100 ~ 200 ℃.