Abstract
This study aimed to clarify the fatigue characteristics of spheroidal vanadium carbide cast iron (SCI-VCrNi) and the fatigue fracture mechanism of cast iron with spheroidal vanadium carbide (VC) dispersed in the stainless matrix microstructure. SCI-VCrNi is not only a high hardness and high toughness material but also has excellent abrasion resistance because of the high hardness (approximately 2300HV) VC dispersed in its matrix.
First, a plane bending test was conducted to clarify fatigue strength, and the results confirmed that the fatigue limit σw to be 358MPa for SCI-VCrNi. Based on these results, a fractographic study was carried out to make clear the fatigue mechanism of SCI-VCrNi. As for SCI-VCrNi, typical fatigue fracture by macro-observation has not been observed due to the large bumps on fracture surface. SEM observation showed the fatigue fracture surface to have typical fatigue striations. In addition, numerous fracture cracks of VC were observed, as well as secondary cracks at the interface between VC and the matrix. These results suggest that the binding strength of VC and the matrix is strong, and crack progress is delayed by VC fracture.
