Electron microscopy study on ''in situ'' carbide formation in martensite of chromium steel

Direct observation of carbide-formation processes at Fe - 0.94% C - 3.8% Cr (wt. %) steel tempering is exercised using the method of thin foil heating in the column of an electron microscope. The following consequence of carbide transformations at tempering is stated: 1)homogeneous production of needle-like precipitants of epsilon-carbide inside martensite crystals; 2)nucleation of M3C cementite particles on epsilon-carbide precipitates with their succeeding growth into matrix; 3)formation of M7C3 chromium carbide