Effect of Annealing Treatment on the Microstructure and Properties of Laser-Clad AlSi10Mg/40%WC Coatings

This study employs laser cladding technology to fabricate AlSi10Mg/40%WC coatings on SiC_p/2009Al substrates, systematically investigating the effects of annealing treatments at 200 ℃, 250 ℃, and 300 ℃ (for 2 hours) on the microstructure and mechanical properties. Analysis by XRD, SEM, and EDS reveals that annealing facilitated Si precipitation and enhanced the uniformity of elemental distribution throughout the coating, while the phase composition remains unchanged. A progressive leftward shift in XRD diffraction peaks with increasing annealing temperature indicates reduced lattice distortion. Mechanical evaluations demonstrate that 250 ℃-2 h annealing decreased microhardness to 238.65 HV (15.9% reduction) while increasing fracture toughness (K_IC) to 31.28 MPa·m^1/2 (17.1% improvement). Wear performance analysis shows a 16.2% reduction in mass loss (decreased from 4.58 mg (unannealed) to 3.84 mg) and a stabilized friction coefficient around 0.30±0.02. Comparatively, while 300 ℃ annealing achieves a slightly higher K_IC enhancement (31.37 MPa·m^1/2), it results in significant hardness degradation (to 223.16 HV) and increased wear loss (to 7.42 mg), attributed to Si phase coarsening. The 250 ℃-2 h annealing treatment achieves a synergistic optimization of hardness, toughness, and wear resistance, providing critical theoretical insights for developing high-performance laser clad composite coatings.