Materials Chemistry and Physics, Vol.224, 169-174, 2019
Microstructural characterization and abrasive wear resistance of a high chromium white iron composite reinforced with in situ formed TiCx
A high chromium white iron (HCWI) composite reinforced with in situ formed 17.2 wt.% TiCx has been prepared. The in situ formed TiCx grains resulting from the decomposition of Ti3AlC2 are round and small. The presence of small TiCx grains effectively inhibited the rapid growth of M7C3 (M: Fe, Cr and other strong carbide formers) carbides, refining the microstructure of composite. High resolution TEM micrographs show that interfaces of TiCx/M7C3 and TiCx/matrix are clean, suggesting the formation of strong bonding interfaces in the composite. The wear behavior of the composite and the unreinforced HCWI material as a function of the normal load in the range of 78-123 N was investigated using dry sliding pin-on-disc wear testing against a YG8 disk under ambient conditions. The wear resistance of HCWI and TiCx/HCWI decreased with increasing load. However, the wear resistance of the TiCx/HCWI composite was over six times that of the unreinforced HCWI material even at the highest load of 123 N. The improved wear resistance of the composite should be ascribed to contributions from both the presence of smaller Tic grains reinforcing the matrix and the refinement of the M7C3 structure. Scanning electron microscopy was used to characterize the microstructures of materials before and after wear testing.