Transient Liquid-Phase Sintering of Ceramic-Reinforced Iron-Based Composites

The microstructural development of ceramic-reinforced Fe-based composites has been studied. The composites were fabricated via powder metallurgy and liquid-phase sintering, a processing route which achieves near-net-shape with good ceramic particulate dispersion. Two matrix alloys were used, Fe--1 wt.% C--1 wt.% Si and Fe--2 wt.% Cu; up to 30 wt.% ( approx 36 vol.%) yttria-stabilized zirconia in the form of approx 20 mu m particles was added to these alloys. The microstructural evolution of these composite materials was studied by examining the densification rate and volume fraction of liquid phase as a function of time. Different particle/matrix interfaces developed in the two composites. A glassy Si-rich layer formed in the Fe--1C--1Si--YSZ composites and a more limited crystalline layer was found in the Fe--2Cu--YSZ composites. Graphs, Photomicrographs, Diffraction patterns. 12 ref.--AA