微合金化及换向轧制对Cu合金晶粒尺寸热稳定性的影响

Effects of microalloying and alternative rolling on thermal stability of grain size of Cu alloy

利用电子背散射衍射分析(EBSD)、透射电子显微分析(TEM)等研究了微量元素添加及换向轧制工艺对Cu合金晶粒尺寸热稳定性的影响。结果表明:经(950℃,10 min)热暴露后,纯Cu的平均晶粒尺寸超过200μm且存在较强的Cube织构。添加0.12%Mg、0.09%Ca、0.10%Y元素后,Cu合金经热暴露后的晶粒尺寸显著减小,同时Cube织构明显弱化而Brass、Copper、S织构的体积分数明显增加。Cu-0.12Mg、Cu-0.09Ca、Cu-0.10Y合金形成的第二相粒子对晶界起到较强的钉扎作用,显著提高晶粒尺寸热稳定性。换向轧制使Cu-0.12Mg和Cu-0.09Ca合金经高温热暴露后的晶粒进一步均匀细化,并且对合金电导率的影响较小。这主要是由于换向轧制抑制了Cube取向晶粒在再结晶过程中的定向生长,并且促进了第二相的弥散析出。

The effects of trace element addition and alternative rolling process on the thermal stability of grain size of Cu alloy were studied using electron backscatter diffraction(EBSD)and transmission electron microscopy(TEM).The results show that the average grain size of pure Cu exceeds 200μm after thermal exposured at(950℃,10 min)and a strong Cube texture forms.The additions of 0.12%Mg,0.09%Ca and 0.10%Y significantly decrease the grain size of Cu alloy after the thermal exposure,which weaken Cube texture obviously and increase the volume fractions of Brass,Copper and S textures as well.The second phase particles in Cu-0.12Mg,Cu-0.09Ca and Cu-0.10Y alloys have a strong pinning effect on the grain boundary and significantly improve the thermal stability of grain size.Alternative rolling leads to a more uniformly distribution of grain size in Cu-0.12Mg and Cu-0.09Ca alloys after thermal exposure,and has little effect on the electrical conductivity of alloy.This is mainly because that alternative rolling inhibits the orientation growth mechanism of Cube-oriented grains during recrystallization process and promotes the more dispersive distribution of second-phase particles.