Ryutaro Jinbou1, Hajime Suto2 and Minoru Nemoto2
1Graduate School, Tohoku University, Sendai. Present address: Hitachi Laboratory, Hitachi Ltd., Hitachi
When alloys are vacuum-deposited on cooled substrates, super-rapidly cooled alloy films in the unequilibrium state can be obtained. As an application of this method, alloy films of Ag-Cu solid solution were prepared in the thickness of about 5 μ, and the changes in their microstructure and mechanical properties with tempering temperature were investigated. The results obtained are summarized as follows: (1) When alloys of about 50%Ag-50%Cu were deposited on metallic substrates placed on a copper plaque cooled with liquid nitrogen, solid solutions containing a small amount of amorphous phase were formed. (2) The solid solution was hardened by tempering at 150°C. The hardening is considered to occur when the solid solution begins to decompose into α and β phases. (3) The Knoop hardness number of a 40 at%Ag-Cu alloy film deposited on a cooled glass substrate was 390 kg/mm2. The as-deposited films were generally very hard but fractured under stresses below their elastic limits. (4) Liquid-quenched 50 at%Ag-Cu alloys consisted of a lamellar structure of α and β, and contained a small amount of γ-solid solution. They showed ductility.
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