Nanostructured powders by mechanical alloying

Different powder grades have been studied and produced by mechanical alloying for Micro-FAST process with the main purpose of developing suitable processing procedure that enables to deliver material in the particle size range required by the process, with suitable nanostructure to facilitate the sintering and control of composition and purity of the material. Improvement of the process yield in view of the optimization of the process has been performed with good results for the Ti based and steel alloys. TiSn metal alloy has been developed to achieve the full control of the microstructure of the powder (without presence of undesired intermetallic compounds) that allow to obtain sintered parts with very fine microstructure, low porosity and suitable properties for selected applications. AISI stainless steel 420 has been produced in a nanostructured version for Micro-FAST with suitable particle size distribution in the fine region (5 to 40 microns) with high efficiency of the mechanical alloying process. NiTi shape memory alloy has been developed by mechanical alloying but further optimisation is needed to reach the requested phase distribution and Shape memory Alloy properties. Post treatment methodologies have been developed to achieved the particle size distribution required for the MicroFAST process and allow the complete handling of powder production under not oxidizing atmosphere: all powders have the requested flowability and can reach full density after the sintering process.