The influence of heat treatment on the microstructure of AISI M2 type high-speed steels modified with powder additions of W and TiB2 was studied. The primary focus was on the effects of austenitizing temperatures on the prior austenite grain size and size distribution, volume fraction, and morphology of the eutectic carbides M2C, M6C, and MC, as well as the character of the secondary precipitation of carbides in the high-speed steels studied. It was shown that austenitizing significantly affects the changes in the chemical composition, morphology, size, and character of distribution of the eutectic carbides in the high-speed steels studied, as well as the volume fraction of retained austenite in the matrix and the prior austenite grain size. These changes in carbides seemed to be induced by a diffusion-induced redistribution of alloying elements between the steel matrix and the carbide phases due to their mutual interaction at high temperatures, which is accompanied by carbide decomposition, coagulation and dissolution and, as a consequence, saturation of the solid solution by alloying elements.

No abstract

No abstract

The transformation of the solidification microstructure and the phase changes in AISI M2 grade high-speed steel modified with powder addition of TiB2have been studied focusing on the effect of austenitising temperatures. In order to investigate kinetics of both the microstructure and phase transformations in eutectic carbides, primarily M2C carbide decomposition, upon heat treatments with respect to diffusion processes, different techniques of electron scanning microscopy, X-ray diffraction analysis and energy dispersive X-ray spectrometry have been used.

No abstract