Microstructure investigation of a SiC whisker reinforced eutectoid zinc alloy matrix composite

The microstructure of a SiC whisker reinforced eutectoid zinc alloy metal matrix composite has been studied by transmission electron microscopy. Precipitation of η particles inside α phase in the matrix was detected, with the orientation relationship, [0001]η∥[1¯11]α,(21¯1¯0)η∥(022¯)α for newly manufactured composite; [21¯1¯0]η∥[011]α,(0001)η∥(11¯1)α for prolonged aged composite. T′ phase was detected in prolonged aged composite. SiC reinforcements were well bonded with the matrix. The interface between the SiC whisker and the matrix was clean and no damage of the material was observed at the interfaces between the matrix and reinforcements. Crystal defects like stacking faults, dislocations and twin were observed in the SiC whiskers. A new phase, Cu5Zn8, was observed near the SiC whiskers.