Mechanical Properties of Discontinuous Precipitated Al-Zn Alloys after Drawing at Room and Cryogenic Temperatures

초록

In order to study the effect of microstructural change on the tensile properties of discontinuous precipitated Al-Zn binary alloy, four different Al-Zn alloys(25, 30, 35, 45 wt% Zn) were aged at 160 degrees C for different aging times(0, 5, 15, 30, 60, 120, 360 min) after being solution treated at 400 degrees C, and successively drawn at room and cryogenic temperatures(-197 degrees C). Discontinuous precipitation was formed during aging in the Al matrix(which contained more than 30 wt% Zn) in Al alloys containing more than 30 wt% Zn. The tensile strength of continuous precipitated Al-35Zn alloy decreased with increasing drawing ratio, however, the tensile strength of discontinuous precipitated Al-35Zn alloy increased with further drawing. The strength and ductility combination, 350 MPa-36% was achieved by drawning discontinuous precipitated Al-Zn alloy at room temperature. The discontinuous precipitated Al-Zn alloy drawn at cryogenic temperature showed a higher value of tensile strength, over 500 MPa, although ductility decreased.

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