Study on the ductility-dip cracking and its formation mechanism of additive manufactured NiCrFe-7A alloy: Effect of the carbon content

摘要

The effect of carbon content on the ductility-dip cracking susceptibility of the additive manufactured NiCrFe-7A alloys was investigated. The temperature-strain curves were measured by using strain-to-fracture test via Gleeble-3500 thermal simulator. Results show that the minimum threshold strains of NiCrFe-7A alloys with low carbon and high carbon are 3.61% and 4.72%, respectively. Higher carbon additions promoted more carbides to precipitate at grain boundaries, then improved the resistance to ductility-dip cracking. Moreover, a higher proportion of twins and recrystallization occurred in the NiCrFe-7A alloy with high carbon was beneficial to hinder ductility-dip cracking propagation.