Microstructuring by selective laser sintering of metallic powder

Parametric analysis of the selective laser melting process

“…Powder binding mechanisms, such as melting and solid-state or liquid-phase sintering, depend on temperature, thus local temperature fields are important for process stability and quality of the fabricated objects [4][5][6].…”

Effects of dispersion technique and component ratio on densification and microstructure of multi-component Cu-based metal powder in direct laser sintering

“…Early experiments on laser sintering of the single-component powder such as Ni, Cu, Pb, Sn, and Zn [5,7] have demonstrated that it was unsuitable for DMLS. Since DMLS is characterized by the extremely short time of laser-powder interaction, typically between 0.5 and 25 ms on any powder particle [5], it can only be realized by liquid phase sintering.…”

“…Thus, the requirements for adjusting laser processing parameters are extremely strict in order to ensure not complete but merely surface melting of particles [6]. However, "balling" phenomena are inevitable in this instance due to higher viscosity and surface tension effects, resulting in a large amount of porosity in the sintered structure [7].…”

“…In the case of pre-alloyed powder, the liquid phase arises when the sintering temperature is between the solidus and liquidus temperatures, and the resulting mixture of solid and liquid phases leads to supersolidus sintering [8]. In the case of multi-component powder, melting one of the components with lower melting point (socalled the binder) forms the liquid phase, and, subsequently, this liquid phase bonds the component with higher melting point (so-called the structural metal) [7]. So far, considerable research efforts have been focused on direct laser sintering of the pre-alloyed powder and the multi-component metal powder.…”

Effects of particle shape and temperature on compaction of copper powder at micro scale

“…PM has not only been used in industrial products but also in medical applications, such as porous metals for use in orthopaedic applications [1]. On the other hand, the direct laser sintering process of metallic powder, which does not require a compaction of powder, has also developed for rapid tooling [2] and producing metallic microstructures [3]. Moreover, it is possible to use a direct powder rolling process for manufacturing titanium strips [4].…”