Competitive failure analysis on tensile fracture of laser-deposited material for martensitic stainless steel

Publication date: 15 March 2017
Source:Materials & Design, Volume 118
Author(s): Shaopeng Wei, Gang Wang, Jianchao Yu, Yiming Rong
Sufficient mechanical properties of deposited materials are needed in remanufacturing applications to guarantee the functionality and reliability of repaired parts. The present paper described the tensile fracture behavior of laser-deposited FV520B martensitic stainless steel comprehensively based on evolution of the microstructure and mechanical property. The samples were fabricated by laser hot-wire deposition. The fracture behavior of the deposited samples was characterized using a specially designed uniaxial tension testing approach and investigated on the grain size, microhardness profile, residual stresses and precipitate distribution. The results show that the tensile fracture occurred at the position with high fluctuating microhardness caused by the multi-layer laser heating. Three tensile fracture patterns of deposited material were found: interfacial fracture, heat affected zone (HAZ) fracture and HAZ/interface hybrid fracture. They result from the competitive failure between microvoid coalescence in the heat affected zone and interfacial cracking in the clad layer/HAZ interface. Grain refinement and dissolution of precipitates occurred in heat affected zone, leading to a decrease of strength and increase of toughness.

Graphical abstract

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