A study on laser sintering of Fe-Cu powder compacts

Abstract

The sintering of Fe-Cu powder compacts by laser beams was studied to determine densification and microstructural development. The influence of processing variables such as Cu content, laser output power, sintering time, and green density on the densification and Brinell hardness (HB) were analyzed, and several temperature curves measured during laser sintering (LS) were also discussed in this article. After LS, the samples exhibited considerable shrinkage, which was very different from the effects of conventional sintering (CS). The main reasons for shrinkage are the laser's very fast heating rates, short sintering times, and relatively high sintering temperatures. As a consequence, insufficient time is available for Fe particles to diffuse in the solid state to form a rigid skeleton. After formation, the liquid penetrates quickly along boundaries and separates the Fe particles, leading to rapid collapse and particle rearrangement, which finally results in considerable shrinkage. An increased Cu content, laser output power, and sintering time can promote shrinkage and hardness, but compact slumping occurs when the laser power is too high.

The Factors Affecting the Swelling of W–Bronze Composite System at Different Sintering Conditions

“…Carbon has high solubility in Fe at temperatures above 910°C. The diffusion of carbon into iron increases the dihedral angle and thereby inhibits swelling brought about by the penetration of the Cu melt into the Fe grain boundary [13]. In this investigation, there were many reasons standing behind the swelling of the sintered compacts.…”

“…It was found that sintering additives which are insoluble in W can segregate to the W interparticle zones and provide a high diffusivity transport path for W atoms which in turn leads to low activation energy for diffusion and bulk transport of the W element [9]. However many previous studies showed that swelling increases in compacts contain lower copper contents [10,11,13]. In homogenous mixtures, swelling occurs only when copper content is lower than certain value.…”

Experimental investigation of laser-assisted powder bed fusion of Fe-Cu powder mixture

“…Fe-Cu powder mixture is one of the first selections for manufacturing of complicated shape and prototypes due to its suitable properties such as high corrosion resistance and superior mechanical properties [30,31]. Schueren and Kruth studied sintering of the Fe-Cu powder mixture and reported that the powder deposition highly depends on the powder properties [32].…”

Effect of Al content on reaction laser sintering of Ni–Al powder

“…It was found that this method cannot sinter large materials because input heat by laser is not enough [6]. In order to overcome this weakness, reactive laser sintering is developed in this study, which uses reactive powders in substituted raw powder compacts [7,8].…”