Effects of processing parameters on direct laser sintering of multicomponent Cu based metal powder

Abstract

Direct laser sintering of a multicomponent Cu based metal powder was successfully processed through the mechanism of liquid phase sintering with partial melting of the powder. The effects of processing parameters such as laser power, scan speed, scan line spacing and layer thickness on the densification and microstructural evolution of the laser sintered powder were investigated. It was found that with increasing laser power or decreasing scan speed, the density of the sintered parts increased and the microstructures became denser. However, the combination of higher laser powers (.400 W) and higher scan speeds (>0 . 06 ms 21 ) gave rise to 'balling' effect. A successive transition from discontinuous scan tracks to coherently joined ones occurs with decreasing scan line spacing. Lowering the thickness of the powder layer promises an improvement in bonding coherence between sintered layers. A single factor termed 'energy density by volume' is defined to evaluate the combined effect of various processing parameters on the density of laser sintered powder. With increasing the energy density by volume up to ,0 . 16 kJ mm 23 , the densification rate is relatively high. However, with intensifying the energy density over ,0 . 23 kJ mm 23 , the mechanism of particle bonding may change into full melting/ solidification, leading to a decrease in the sintered density.

Microstructure characteristics and formation mechanisms of in situ WC cemented carbide based hardmetals prepared by Selective Laser Melting

“…Increasing the applied scan speed v lowers the obtainable LED, which in turn decreases the SLM temperature T [28][29][30]. The activity of carbon within the melts, consequently, is enhanced, as revealed from Eq.…”

Balling behavior of stainless steel and nickel powder during selective laser melting process

“…The balls were classified as plate, cup, and sphere according to shape designation, and the respective formation mechanisms were also analyzed in their research. Gu et al investigated the balling behavior of Cu-based and stainless steel under the action of CO 2 laser [7,14,15]. They pointed out that balls can be divided into two types: The first kind of ball formation was due to inadequate laser energy input with little liquid content, and the second kind of ball was owing to molten pool splashing under high scan speed.…”

Novel Aluminum Based Composites by Selective Laser Melting (SLM) Additive Manufacturing (AM): Tailored Formation of Multiple Reinforcing Phases and its Mechanisms

“…Among these parameters, we chose a fixed laser scan speed ( v) of 100 mm/s and four various laser powers ( P) of 80, 90, 100, and 110 W in the present study, in order to vary the SLM processing conditions. The "linear laser energy density" (LED), which was defined by [41,42]:…”