Microstructure evolution and wear behaviour of VN strengthened 17-4PH stainless steel fabricated by metal injection molding

Metal injection molding (MIM) is a technique for fabricating metallic parts of complicated shapes, and 17-4PH stainless steel is one of the most effective materials in resistance to corrosion. The microstructural evolution of 17-4PH stainless steel added with VN at different amounts is investigated for MIM specimens, and the micro-hardness, wear coefficients, and wear losses of these specimens had been characterised. After heat treatment, martensite, austenite and ferrite existed for specimens added with VN and segregation of VN is observed as the addition increased to 8wt%. Compared with MIM 17-4PH stainless steel, the hardness of the specimens increased with VN. The sintered specimens exhibit a decrease in friction coefficients and an increase in the running-in period with VN. The wear loss and wear scars width of the specimens decrease with VN. The specimens with VN are more wear-resistant and the specimens with 12wt% VN yield the least wear loss among all the specimens. Heat treatment is beneficial to improve wear resistance of the specimens.

Automated summary

The study found that after heat treatment, the hardness of MIM specimens added with VN improved, while the wear loss and wear scars width decreased, indicating better wear resistance.