【作者】 高凤华； 田妮； 丛福官； 赵刚；

【Author】 GAO Fenghua~1 TIAN Ni~1 CONG Fuguan~2 ZHAO Gang~1 1.Key Laboratory for,4nisotropy and Texture of Materials(Ministry of Education),Northeastern University,Shenyang 110004,China; 2.Northeast Light Alloy Co.,Ltd.,Harbin 150060,China

【机构】 东北大学材料各向异性与织构教育部重点实验室； 东北轻合金有限责任公司；

【摘要】 本文采用 DSC、金相、扫描电镜及能谱分析、X 射线衍射相分析等方法,研究了7050合金φ200mm 半连续铸锭的结晶相及其在470℃均匀化处理过程的变化规律,结果表明:7050合金半连续铸锭中存在大量非平衡凝固共晶体,其过烧温度为477℃,其晶体中的非基体共晶相为 MgZn₂型晶体结构的含有 AlZnMgCu 元素的非平衡第二相;在均匀化处理过程该非平衡凝固共晶体不仅向合金基体溶解还转变成 Al₂CuMg（S 相）, S 相在该合金中的熔化温度为490℃左右:在470℃均匀化处理时,φ200mm7050合金半连续铸锭中含 Zn 结晶相于12小时前全部消失,其中部分形成的 S 相,但在470℃均匀化处理时,S 相不能完全溶入合金基体。铸锭中还存在少量的块状 Al₇Cu₂Fe 相,均匀化处理过程基本不变。更多还原

【Abstract】 The constituents of the Φ200mm semicontinous casting ingot of 7050 aluminum alloy and their evolution during homogenization treatment at 470℃ have been studied by differential scanning calorimetry（DSC）,optical microscopy（OM）, scanning electron microscopy with energy dispersive X-ray spectroscopy（SEM-EDX）and X-ray diffraction analysis.The results show that the semicontinous casting ingot of 7050 aluminum alloy presents a large number of nonequilibrium eutectic whose the overheating temperature is 477℃,one phase in the eutectic is a nonequilibrium second phase which contains AlZnMgCu with the crystal structure of MgZn₂.During homogenization treatment processing,nonequilibrium eutectic not only dissolves into the matrix of the alloy,but also transforms to Al₂CuMg（S phase）which melts at 490 ℃ in this alloy.When homogenizing at 470℃,Zn in the second phase in the nonequilibrium eutectic in the Φ200mm semicontinous casting ingot of 7050 aluminum alloy dissolve into its matrix completely before homogenization treatment for 12h,and the residue transforms to AI2CuMg（S phase）,however, Al₂CuMg（S phase）can not dissolve completely when homogenizing at 470℃.There are a few block Al₇Cu₂Fe phases in the alloy,which change a little after homogenization treatment.更多还原