摘要
选取成分为Al-3Mg-20Cu的三元包共晶合金,在阶梯型金属铸型冷却的自由凝固实验中,通过不同壁厚处的组织演化,对其凝固过程和凝固机理进行了分析。实验结果表明:位于包共晶PE点左侧较远处的Al-3Mg-20Cu合金凝固过程为L→(L+α)→(L+α+θ)→(L+α+θ+S),凝固组织为初生α-Al相、θ-Al_(2)Cu相、二元共晶α+θ和三元共晶α+θ+S相组成。初生α-Al相呈现非小平面的凝固特性,θ-Al_(2)Cu相呈现小平面的凝固特性,并且随着冷却速度的提高,组织得到明显的细化,θ-Al_(2)Cu相小平面的凝固特性得到了一定程度的弱化。
The ternary quasiperitectic alloys with composition of Al-3Mg-20Cu were selected to carry out solidification experiments under the different cooling rates.And then the solidification path,microstructure evolution and solidification mechanism were analyzed.The experimental results show that a ternary eutectic reaction occurred in the Al-3Mg-20Cu alloy which was located in the far left of quasiperitectic point PE.the solidification paths of this alloy are L→(L+α)→(L+α+θ)→(L+α+θ+S),during the whole solidification the ternary eutectic reaction did not occurred.There were a amount of primaryα-Al phases,θ-Al_(2)Cu phase and binary and ternary eutectic structures in the solidification structures.The primaryα-Al phases in the Al-3Mg-20Cu alloy appeared non-faceted suface solidification characteristic,Theθ-Al_(2)Cu phases in the Al-3Mg-20Cu alloy appeared faceted suface solidification characteristic.With the increase of solidification velocity,the grain were refined obviously.Theθ-Al_(2)Cu crystal phase phases undergoes a faceted-non-faceted transition.
作者
唐玲
夏鹏举
TANG Ling;XIA Peng-ju(School of Materials Science and Engineering,Shaanxi University of Technology,Hanzhong 723000,China)
出处
《陕西理工大学学报（自然科学版）》
2021年第3期1-6,13,共7页
Journal of Shaanxi University of Technology:Natural Science Edition
关键词
包共晶合金
AL-CU-MG
组织演变
凝固机理
小平面
非小平面
ternary quasiperitetic alloy
Al-Cu-Mg alloy
microstructure evolution
solidification path
faceted suface
non-faceted suface
