Strength and Ductility of 7000 Series Wrought Aluminum Alloys as Affected by Ingot Structure

摘要

A study was made of the effect of ingot structure on the strength and ductility of high strength wrought aluminum alloys. It was found that a fine cast structure facilitated complete homogenization which, in turn, resulted in significant increases in ductility and strength. A completely homogenized 7075-T6 alloy developed tensile properties of 85,000 psi ultimate tensile strength, 75,000 psi yield strength, with 40 percent reduction in area. Completely homogenized 7001-T6 alloy tensile properties were 102,000 psi ultimate tensile strength, 99,000 psi yield strength, with 19 percent reduction in area. A method was devised for making small ingots having secondary dendrite arm spacing of less than 10 microns. This method involved multiple pass arc melting of commercial rolled plate with a tungsten electrode. This material could be completely homogenized after 3 hours at 900F; homogenization of the original plate material was not complete after 120 hours at 900F. Degree of homogeneity was determined by use of metallographic and electron microprobe analyses. The electron microprobe study also showed the preferential segregation of solutes in the microstructure. (Author)