Abstract
In this paper, the microstructure and mechanical properties of the SG-CuAl8Ni6 Ni-Al bronze straight wall were studied, which was fabricated by the cold metal transfer (CMT) arc additive manufacturing technology. This Ni-Al bronze cladding layer of SG-CuAl8Ni6 is composed mainly of α-Cu, residual β phase, rich Pb phase and κ phase. The microstructure of this multilayer single-channel Ni-Al bronze straight wall circulating presents the overall periodic law, which changes from fine cellular crystals, columnar crystals to dendritic crystals with the increase of the distance from the substrate. The Vickers hardness value of the Ni-Al bronze straight wall decreases with the distance of substrate are between 155 and 185 HV0.5. The microhardness and elastic modulus of the Ni-Al bronze specimen are 1.57 times and 1.99 times higher than these of the brass matrix, respectively. The ultimate tensile strength (UTS) of the straight wall in the welding direction and 45° downward-sloping is greater than that of about 550 MPa in the stacking direction, and the elongation value in the welding direction is the highest. With the increase in interlayer temperature, the grain size increased gradually, and the tensile strength decreases slightly.
Highlights
Copper alloys, with its excellent thermal and electric conductivity as well as mechanical properties, are widely used in the electrical, lighting and machinery fields
Wang et al (2021) used Laser Engineered Net Shaping technology, cold metal transfer (CMT) Additive Manufacturing Nickel Aluminum Bronze have prepared Ti-Ni-C gradient composites with high hardness and wear resistance, which can be used for equipment, size and cutting tools, Hunter Martin et al (2020) achieved grain refinement when using the laser additive manufacturing process by adding Al3Ta and Al3Zr to aluminum alloy powder materials, and believed that the method could be extended to other alloys such as iron, nickel and titanium alloys
The cladding layer’s internal microstructure presents an obvious gradient structure: the cladding layer and substrate combination area near the fusion line area of the microstructure are mainly for the tiny cell, in the region far away from the fusion line, columnar crystals grow perpendicular to the direction of welding (Figure 2A) and gradually it turns to dendrites (Figure 2B)
Summary
With its excellent thermal and electric conductivity as well as mechanical properties, are widely used in the electrical, lighting and machinery fields They have good corrosion resistance to seawater and marine organisms, and are suitable to manufacture parts in the shipbuilding industry (Wang et al, 2020a). It has been shown that Laser additive manufacturing technology can improve production efficiency, have high material utilization rate, small shrinkage, and can obtain parts with excellent performance (Zhang and Chen, 2019; Chen et al, 2021) This point of view is proven by Wang et al (2020), who used SLM technology to prepare Cu-15Ni-8Sn alloy forming parts that showed good strength and toughness. In the comparative study of Surinder Singh (Singh et al, 2019) on 316 L stainless steel laser cladding layer on the surface of a pure copper, it was found that the cladding layer was produced with a large number of holes, porosity and other defects, meaning that the strength, density and thermal conductivity of the pure copper cladding layer was lower than those of the cold spaying pure copper coating, because the high heat input leads to particle melting, high local temperature, high cooling rate and diffusion of carbon element in the cross-section
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