Intensive laser repair through additive manufacturing of high-strength martensitic stainless steel powders (II): evaluation of intensive repair ability of high strength martensitic steel powder based on Schaeffler diagram

As one of the key technologies for intensive additive repair (i.e., using a type of powder to repair various substrates), the method of accurately predicting the strength of repaired samples based on the chemical composition of filling materials and base materials needs to be explored urgently. An intensive additive repair experiment based on the laser coaxial powder feeding cladding technology was carried out using an independently designed intensive high-strength martensitic stainless steel (IHMSS) powder and eight types of substrates. A new approach was presented: the distance between the composition points of the IHMSS powder and the substrate to be repaired, as shown in Schaeffler's diagram (D), and their orientation relationship (θ) can provide a basis for describing the bonding strength of the repaired interface between the aforementioned materials. With the increase in D and θ, the ratios of tensile strength and elongation of additive repair parts to those of base materials decreased. When θ was below 1.12, the tensile strength of repaired interface in the normal direction was more than 83% that of the substrate to be repaired. Incomplete fusion and cracks were found on the cross section of the additive parts when θ exceeded 1.12. When D exceeded 13%, a high microhardness phase was formed near the interface. Further analysis results show that, with the increase in D and θ, the gradients of microstructure, composition, and microhardness at the repaired interface will be increased.