Abstract
Isothermal aging at 773∼1023 K has been carried out to investigate precipitation in low Fe, high Cr, Ni-base overlay weld alloys which were formed on a mild steel by plasma powder welding process. In this work, effects of NbC addition on precipitation process were studied by hardness measurements, X-ray diffraction and metallographic methods.It was found that the NbC dispersed alloy was higher in age-hradenability than the NbC-free alloy in the as-welded condition and both alloys had a peak hardness followed by slowly softening during aging. In the NbC-free alloy, nodular precipitates appeared at grain boundaries and then continuous precipitation of α′-phase occurred within the matrix (γ-phase). However, in the NbC dispersed alloy, any precipitaion has not occurred except for continuous precipitation of α′ in the matrix. It was considered that such different precipitation phenomena have been caused by niobium atoms dissolved in the matrix. Age hardening observed is due to the continuous precipitation of α′ particles and the softening is caused by their coarsening.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of the Japan Institute of Metals and Materials
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
