The processing-property relationship of a model cryogenically mechanically alloyed polymer-polymer system [polycarbonate (PC) and poly(aryl ether ether ketone) (PEEK)] was investigated. PC and PEEK powders were cryogenically mechanically alloyed for 10 h, and the resulting two-phase powder particles were processed into testable coupons with a miniature ram-injection molder. The bulk mechanical properties of the coupons made from the mechanically alloyed powders and nonmechanically alloyed powders were investigated as a function of mechanical alloying and injection-molding parameters. The injection-molded coupons were mechanically tested in the three-point-bending mode. The results demonstrated that no measurable improvement was achieved in the energy to break, strain at failure, or failure strength in the coupons made from the mechanically alloyed materials in comparison with those of the coupons made from the nonmechanically alloyed powders. (C) 2003 Wiley Periodicals, Inc.