Cracking inhibition and strengthening of FeCrAlY alloy through addition of TiC nanoparticles during laser melting deposition

Abstract

FeCrAlY alloy is one ideal candidate for nuclear fuel cladding. Laser melting deposition (LMD) provides a new method for its preparation. To solve the cracking problem as well as to strengthen the alloy, TiC nanoparticles were added during the LMD process. The results show that 4 wt% TiC addition can fully suppress crackings by prompting columnar to equiaxed grain transition. When TiC addition is 6 wt%, the alloy has the finest average grain size of 17 μm, which is nearly 13 times smaller than that without TiC addition. TiC addition also prompts the escape of gas in the molten pool, thus reduces the porosity of the alloys. Without TiC addition, the alloy contains Y-rich heterogeneous structured particles, including Y–O, Y–O–Al–Cr, and Y–O–Al–Cr–Fe particles. After adding TiC, other Y–O–Al–Cr, Y–Al, and C–O–Cr–Fe particles can also be observed. TiC particles mainly have flower-like/granule and plate-like shapes, which correspond to primary and eutectic particles, respectively. With 8 wt% TiC addition, the alloy has good mechanical properties with yield strength of 488 ± 25 MPa, ultimate tensile strength of 749 ± 47 MPa, and an elongation of 15 ± 2%, which are close to those prepared by traditional thermo-mechanically deformation processes.