Microstructure and Wear Resistance of a Cr7C3 Reinforced Ni3Al Composite Coating Prepared by Laser Cladding

Abstract

Using Cr7C3/Ni3Al alloyed powder and Cr3C2/Ni3Al mixed powder, laser cladding was carried out to prepare a Cr7C3 reinforced Ni3Al composite cladding layer. The microstructure and tribological properties of the cladding materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and wear tests. The results indicate that the microstructure of the Cr7C3/Ni3Al alloyed powder cladding layer contains mainly Ni3Al, NiAl, and in situ-formed Cr7C3, whereas Cr3C2 occurs in the Cr3C2/Ni3Al mixed powder cladding layer. The friction coefficient and wear loss of the alloyed powder cladding layer are about 0.1 and 0.75 mg, respectively, which are less than those of the mixed powder cladding layer (0.12 and 0.8 mg). Moreover, the alloyed powder cladding layer is much friendlier to its counterpart. The counterpart’s loss weight of the alloyed powder cladding layer decreases 42.2% than the mixed powder cladding layer. The reason can be attributed to the homogeneous distribution of fine in situ-formed Cr7C3 in the alloyed powder cladding materials, which can effectively separate the friction pair, improving the wear resistance of the cladding materials.

The Effect of Laser Power on the Microstructure and Wear Resistance of a Ni3Al-Based Alloy Cladding Layer Deposited via Laser Cladding

“…When the power was high, the size of Cr 7 C 3 became coarse, the area of Cr 7 C 3 was relatively low, and the distribution of Cr 7 C 3 was irregular. Related studies have shown that the carbide size has a certain influence on the wear resistance mechanism of the laser cladding layer [16]. In the friction process, large Cr 7 C 3 particles can effectively separate the grinding pair and reduce the friction coefficient and friction shear force.…”

“…Thus, a laser cladding layer with good wear resistance and high microhardness was obtained. Liu et al [16] used a Ni 3 Al + Cr 3 C 2 mixed powder and a Ni 3 Al/Cr 7 C 3 alloy powder to perform a laser cladding experiment, and the results showed that the microstructure of the laser cladding layer was uniform and dense, without defects, and showed metallurgical bonding with the substrate. Due to the high laser energy density and the fast cooling rate of the laser cladding layer, laser cladding technology has the effect of grain refinement and solution strengthening.…”

Effect of Process Parameters on the Microstructure and Wear Resistance of Fe3Al/Cr3C2 Composites

“…This indicates that Cr 3 C 2 can serve as an excellent strengthening phase for composite materials and can improve the performance of alloys. Liu et al [18] prepared a Ni 3 Al/Cr 3 C 2 -composite wear-resistant coating on a 42CrMo base material, and proposed a wear model of the composite material based on the results of experiments on friction and wear. This model proposes a softer Ni 3 Al phase as the base, with harder carbide particles embedded in it.…”