Fabrication of graded-boundary Cr/steel material by laser beam and electron beam Available to Purchase

For the development of thick metal/metal graded-boundary materials, the fabrication of Cr/Steel graded-boundary material was carried out by high density energy beam. In order to produce compositionally graded boundary layer between substrate steel and added Cr metal, a series of surface alloying treatments was performed with both CO₂ laser and electron beam. Cr sheet was placed on low carbon steel, and then CO₂ laser beam was irradiated on that surface to produce a homogeneous alloyed layer. On this first surface-alloyed layer, another Cr sheet was placed and CO₂ laser beam was irradiated again to produce second surface-alloyed layer. Sequential repetition of laser surface alloying treatment 4 times resulted in a compositionally graded region with the thickness of about 2mm from 60% of Cr and 40% of Fe in surface region to 0% of Cr and 99% of Fe in substrate. Similar procedures were carried out by electron beam surface alloying treatment to produce Cr/Steel graded-boundary material. Sequential surface-alloying treatment 4 times resulted in a compositionally graded region with the thickness of about 1mm from 60% of Cr and 40% of Fe in surface region to 0% of Cr and 99% of Fe in substrate. In both cases, any visible root porosities were not found in graded-boundary region. Since the structure of both high Cr graded-boundary region and substrate were same BCC structure, volume change was almost absent and thus any appreciable cracks were not formed in boundary region between alloyed region and substrate even in rapid cooling.