Processing of Cu-Al-Ni and Cu-Zn-Al Alloys by Mechanical Alloying

Abstract:

The mechanical alloying process provides alloys with extremely refined microstructure, reducing the need for alloying elements to grain growth restriction, as in casting techniques. The Cu-Al-Ni and Cu-Zn-Al alloys produced by casting may have the shape memory effect when plastically deformed at relatively low temperatures, returning to its original shape upon heating at a given temperature. This work aimed at the production of Cu-Al-Ni and Cu-Zn-Al alloys by mechanical alloying, followed by microstructural characterization and investigation of the shape memory effect by means of differential scanning calorimetry (DSC). Metal powders of Cu, Al, Ni and Cu, Zn, Al were processed in a SPEX high energy vibratory mill during 8 hours, with ball-to-powder weight ratio of 5:1. The milled products were characterized by X-ray diffraction. For each alloy, specimens with 8 mm diameter and 2 mm thickness were shapes by uniaxial pressing, sintered in a tube furnace with argon atmosphere, solubilized and then quenched in water. Samples were characterized by optical and scanning electron microscopy (SEM), Vickers hardness testing and DSC. An ultrafine microstructure was obtained in the Cu-Al-Ni alloy but the shape memory effect was not detected by DSC analysis because of second phase precipitation. The shape memory effect was not present in the Cu-Zn-Al alloy also, because of zinc oxidation during the sintering.

• Periodical: Materials Science Forum (Volumes 727-728)
• Pages: 200-205
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.727-728.200
• Online since: August 2012
• Authors: André Victor Traleski, Selauco Vurobi Jr., Osvaldo Mitsuyuki Cintho
• Keywords: Copper-Based Alloys, Mechanical Alloying, Microstructure, Shape Memory Effects (SME)

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