Synthesis, selective laser sintering and post-processing of metal and ceramic composites

Selective Laser Sintering (SLS) is a rapid prototyping technique by which three-dimensional parts are created directly from a CAD/CAM database without part specific tooling. Nanocrystalline materials can lead to improved mechanical and physical properties. Ceramic and ceramic-metal composite powders such as {dollar}rm YBasb2Cusb3Osb{lcub}7-x{rcub}{dollar} and Ag-{dollar}rm YBasb2Cusb3Osb{lcub}7-x{rcub}{dollar} were synthesized by sol-gel processing routes to produce nanocrystalline powders suitable for SLS. The composite powders were studied and characterized for their homogeneity, structures and thermal behavior by analytical techniques. SLS of the nanocrystalline composite powders was done to create porous preforms. In addition, commercial metal powder systems such as Bronze (10Wt.% Sn) - Nickel powder mix and Nickel-based superalloys were processed by SLS. SLS of the powders was investigated under different SLS processing conditions, such as laser power, scan speed, scan direction, scan spacing, and layer thickness, to optimize desirable microstructures and properties. The mechanical properties of SLS parts were evaluated and correlated to the part density. Subsequently, the mechanical properties and part density were correlated to the microstructure and SLS processing parameters.; To make the SLS porous parts structurally sound, post-SLS processing such as liquid phase sintering (LPS), infiltration and hot isostatic pressing (HIP) was done, without loss of shape. The post-SLS processing conditions, such as time, temperature, pressure, etc., were varied to study the resultant densification and mechanical properties. The resultant densification and mechanical properties were studied and related to microstructures and P/M densification models. These results are then correlated to the SLS processing parameters.