Relationships between Porosity and Elastic Modulus of Sintered Copper-Nickel Alloys Made from Mixed and Mechanically Alloyed Powders

In this study, the relationships between porosity (P) and elastic modulus of sintered copper-nickel alloys made from mixed powder and mechanically alloyed powders were investigated by an acoustic pulse method. The elastic modulus of sintered alloy made from mixed powder differed from that made from mechanically alloyed powder below 50 mass% copper content. Especially, the difference of Poisson's ratio was clearly observed in the range above 0.05 of porosity. Irrespective of the copper contents or the powders mixed or mechanically alloyed, Young's modulus (E) and shear modulus (G) were described as E = (E0-KE·P)(1-P) and G = (G0-KG·P)(1-P), respectively, when E0 and G0 are E and G at P = 0, KE and KG are experimental constants for E and G, respectively. The E0, G0, KE and KG were cubic functionally decreased with increasing of the copper content. By using above relation, it was clarified that elastic modulus of the sintered copper-nickel alloy can be calculated from two parameters, copper content and porosity.