熔体过热处理对Al-4.7%Cu合金定向凝固力学性能及晶体取向的影响  

Influence of Melt Superheating Treatment on the Mechanical Property and Crystal Orientation of Directionally Solidified Al-4.7%Cu Alloy

作　　者：司乃潮[1] 孙克庆[1] 

机构地区：[1]江苏大学材料科学与工程学院,江苏镇江212013

出　　处：《铸造》2007年第7期683-686,共4页Foundry

摘　　要：在熔体过热温度Ts分别为750、850、950、1050℃时,研究熔体过热温度对Al-4.7%Cu合金定向凝固组织及力学性能的影响,利用综合热分析仪测定Al-4.7%Cu合金熔体结构特征及变化过程,用扫描电镜观察断口形貌。结果表明,定向凝固试样力学性能与非定向凝固的相比,强度提高60%,断后伸长率提高近1倍。断口形貌观察表明,富Cu相明显减少,韧窝数量显著增加。随熔体过热温度提高及过热时间延长,试样强度及塑性提高,随低温保持时间延长,试样强度及塑性变差。Al-4.7%Cu合金枝晶沿择优方向<100>生长,且随熔体过热温度提高,(100)晶面衍射强度减弱,表明晶面取向产生分支。Al-4.7%Cu合金过热处理会使熔体结构(即团簇结构)发生一定变化。With the temperature of 750 ℃, 850 ℃, 950 ℃ and 1 050 ℃, the influence of melt superheat temperature Ts on the solidification microstructure and mechanical performance of directionally solidified Al-4.7%Cu alloy was studied. The characteristics of the melt were measured by universal thermo-analyzer. And the fracture morphology was analyzed by SEM. The results show that the mechanical property of directionally solidified sample was much better, the strength is increased by 60% and the elongation can be doubled. The fracture morphology shows that Cu-rich phase decreases obviously and dimple number increases evidently. The higher the melt superheating temperature and the longer the superheating time the better are the strength and plastic. However, with the holding of low temperature, the strength and plastic get a decrease. The dendrites of Al-4.7%Cu alloy prefer 〈100〉 to grow. As the melt superheat temperature growing, the diffraction intensity of （110） crystal face weakens, which indicates that the crystal orientations have embranchment. The superheating treatment of Al-4.7% Cu alloy makes the alloy microstructure changed.

关 键 词：过热处理 定向凝固 凝固组织 力学性能 断口形貌 

分 类 号：TG111.4[金属学及工艺—物理冶金] TG146.21[金属学及工艺—金属学]