Accession Number : AD0475357

Title :   SUPERPLASTICITY IN AN ALUMINUM - ZINC ALLOY.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Chumley, Sylvester G. ; Meinig, George R., Jr.

Report Date : 1965

Pagination or Media Count : 80

Abstract : Recent investigations have demonstrated remarkable ductility in a 20 wt-% aluminum - 80 wt-% zinc alloy. An understanding of the mechanisms responsible for this superplastic behavior could have important applications in other commercial alloy systems. This investigation consists of correlated metallographic examination, X-ray diffraction analysis, and tensile testing of Al-Zn binary alloys of 17, 20, and 23% aluminum at specific stages of treatment. Special attention is focused on the heat evolution which follows quenching, a phenomenon apparently associated with the spontaneous breakdown of the unstable alpha' structure. Of particular interest is the appearance of a disorganized, undefined structure after the heat evolution as evidenced by diffraction analysis. The subsequent organization of this structure and apparent diffusional effects as aging takes place at room temperature is clearly indicated by experimental evidence. The lack of three-dimensional periodicity in space following quenching from the single phase region suggests a strong analogy between the alloys studied and the viscous behavior of glass-like materials. (Author)

Descriptors :   (*ALUMINUM ALLOYS, PLASTIC PROPERTIES), (*ZINC ALLOYS, PLASTIC PROPERTIES), METALLOGRAPHY, X RAY DIFFRACTION, TENSILE PROPERTIES, THERMAL PROPERTIES.

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE