The effects of alloying elements on uniform elongation of 1420 MPa grade tempered martensite

The effects of alloying elements addition on uniform elongation of tempered martensite has been investigated. Tempered martensite is considered as dua l phase structure composed of ferrite matrix and harder second phase: cemen tite. Cementite volume fraction and morphology were observed by scanning an d transmission electron microscopy. Microstrain of ferrite matrix were eval uated by means of X-ray diffraction analysis. It was observed that Carbon a ddition effectively increased uniform elongation. It was explained that hig h cementite volume fraction contributed to high uniform elongation. It was also observed that Silicon addition increased uniform elongation remarkably . It was considered that Silicon addition led to refinement of cementite an d extremely low microstrain of matrix and both of them contributed to high uniform elongation.