FIBER BREAKAGE IN PROCESSING POWDER INJECTION MOLDED METAL MATRIX COMPOSITES

摘要

Fiber length and fiber content have significant impact on the improvement of strength properties of composites. Fiber breakage occurs during processing of composite materials. This study presents the results of changes in fiber length during various steps of powder injection molding (PIM). An optical imaging method was used for measurement of changes in fiber length. In this research, composite mixes were compounded and investigated to study the effects of fiber contents and the binder viscosity on the fiber length reduction. Conventional molding and multiple live-feed molding (MLFM) were used to produce test samples. The effects of macro-shear induced by MLFM on the fiber length reduction were noted. Results showed that compounding caused 50% fiber breakage while granulation caused 20% additional fiber damage. Fiber fracture was increased to approximately 88% in injection molded test bars. Samples produced by MLFM showed approximately 1% higher fiber fracture compared to the test bars produced by conventional molding.