Metallic Glass Formation Upon Rapid Solidification of Fe60Cr8Nb8B24 (at%) Alloy through LASER Cladding and Remelting

Abstract

Fe 60 Cr 8 Nb 8 B 24 (at%) amorphous powder and ingot were submitted to LASER cladding and remelting process, respectively. Fe-based coatings were produced using different LASER processing parameters and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Vickers microhardness. All coatings obtained by LASER cladding (LC) and layers obtained by LASER surface remelting (LSR) with shorter and median interaction times (scanning speeds of 16.7 and 66.7mm/s), irrespective of overlap value, presented peaks of the crystalline phases α-Fe, Fe 2 B and the FeNbB intermetallic. In addition, layers obtained by LSR with shorter interaction time (150mm/s), in general, presented only peaks of the α-Fe and Fe 2 B phases, except that produced with overlap value of 20%, more amorphous. SEM results showed that, regardless of LASER process, the coatings presented cracks, some pores and FeNbB intermetallic phase. All coatings obtained by LC and that obtained with shorter interaction time, by LSR, showed a Vickers microhardness, 1086 to 1329HV and 2161 to 2294HV, respectively, significantly higher than the substrates, AISI steel: 170HV and Fe-Cr-Nb-B: 1921HV.

Laser Cladding of Fe-based Metallic Glass/MoS2 Self-lubricating Composites: Effect of Power and Scanning Speed

“…These layers were clad using different laser powers (200, 400, 600 and 800 W) and scanning speeds (150, 100, 66.7, 33.3 and 16.6 mm/s), which resulted in a variation of the energy density from 7 to 240 J/mm 2 . These parameters were chosen considering a previous work with the Fe 60 Cr 8 Nb 8 B 24 (at%) alloy 11 . The five scanning speeds were used in combination with each power to prepare twenty different single tracks.…”