STATIC AND DYNAMIC PRECIPITATION FROM SUPERSATURATED SOLID-SOLUTION OF NICKEL-ALUMINUM BRONZE

The paper presents the results of investigations of the mechanical pro perties and analysis of structural changes induced by static and dynam ic precipitation in CuNi14Al3 alloy deformed at the temperature range of intensive precipitation (673-823 K). During isothermal decompositio n of a supersaturated solid solution, the hardening occurs as a result of continuous and discontinuous precipitation of the gamma' phase (Ni 3Al). Plastic strain of CuNi14Al3 alloy at temperatures lower than the solvus temperature induces precipitation- strain hardening. The dynam ic decomposition of the supersaturated solution is very fast, but the magnitude of the obtained hardening is smaller than that obtained duri ng isothermal ageing. Introduction of strengthening phases as a result of pre-ageing prior to deformation yields great hardening when the st rengthening particles are continuous precipitates of the gamma' phase. Strong hardening of alloy can be obtained also when the supersaturate d solid solution is subjected prior to ageing to plastic strain (epsil on = 0.2) at ambient temperature. Smaller but stable hardening is obta ined when before ageing the alloy is subjected to deformation (epsilon = 0.2) at the temperature of subsequent ageing.