Mechanical Properties of Cu-20%Nb and Cu-20%Ta In situ Composites between 22 and 600C

摘要

The effect of initial dendrite size and dendrite modulus on the mechanical properties of in situ composites was evaluated. Decreasing the initial dendrite size, which is in effect the same as decreasing the dislocation barrier spacing, increases the ultimate tensile stress and ductility. Increasing the modulus of the dendrites or filament material also increases the ultimate tensile stress appreciably. The effect of temperature on the ultimate tensile stress was also investigated. It was found that the strength of Cu-20%Ta was higher than that of Cu-20%Nb at all temperatures and annealing conditions, and both exhibited an age hardening phenomenon at 150/degree/C. The decreases in strength with temperature were explained up to 300/degree/C by the expected decreases in strength based on the decrease in shear modulus of Cu and beyond that by filament coarsening. 43 figs. (ERA citation 14:017735)