Investigations on dry sliding of laser cladded aluminum bronze

Abstract

-The aim of this study was to investigate the tribological behaviour of laser cladded aluminum bronze tool surfaces for dry metal forming. In a first part of this work a process window for cladding aluminum bronze on steel substrate was investigated to ensure a low dilution. Therefore, the cladding speed, the powder feed rate, the laser power and the distance between the process head and the substrate were varied. The target of the second part was to investigate the influence of different process parameters on the tribological behaviour of the cladded tracks. The laser claddings were carried out on both aluminum bronze and cold work tool steel as substrate materials. Two different particle sizes of the cladding powder material were used. The cladding speed was varied and a post-processing laser remelting treatment was applied. It is shown that the tribological behaviour of the surface in a dry oscillating ball-on-plate test is highly dependent on the substrate material. In the third part a deep drawing tool was additively manufactured by direct laser deposition. Furthermore, the tool was applied to form circular cups with and without lubrication.

A Study of Characteristics of Aluminum Bronze Coatings Applied to Steel Using Additive Technologies

“…Such precipitates are typical of processes involving a supercooled liquid phase as well as for non-equilibrium crystallization in the Cu-Fe system [16][17][18][19][20]. The precipitation of spherical iron particles in the tested samples is consistent with experimental data obtained by Freiße et al [11] and Dai et al [21] on the microstructure of an aluminum bronze coating obtained by laser cladding.…”

“…The observed microstructure of the HAZ is comparable with the microstructure of welded joints. The obtained data on the HAZ of experimental samples can be compared with the results by Freiße et al [11], where in the zone bordering the deposited bronze coating, the microhardness of the steel shows a maximum and is about 600 HV, which indirectly indicates the formation of a heat-affected zone with nonequilibrium crystallization.…”

“…According to Alam et al [8], the microhardness of aluminum bronze coating applied to steel by plasma spraying varied from 100 to 160 HV depending on the spraying conditions, which was on average one and a half times less than for our test samples. Furthermore, Freiße et al [11] shown that the microhardness of the coating of the same grade of aluminum bronze deposited by laser on steel, averaged 200-220 HV.…”

“…Along with electric-arc [7] and plasma spraying [8], the method of applying bronze coatings using additive technologies is considered one of the most promising nowadays. However, there are few papers studying additive application technologies and characteristics of the resulting coating [9][10][11][12]. Thus, Schmidt et al [9] described the process of applying aluminum bronze on stainless steel tools using the direct laser deposition (DLD) method.…”

“…Liu et al [10] described the shaped metal deposition (SMD) technique of applying bronze to low-carbon steel and was good bronze-steel adhesion, which was achieved, among other things, by the diffusion of silicon into iron with the formation of solid solutions. Freiße et al [11] studied tribological characteristics of aluminum bronze coatings applied to steel by laser cladding. It was noted that the characteristics of the coating may depend on laser power.…”