Fernand Marquis

Abstract:

Because the strength, toughness, and other engineering properties of heterogeneous materials are strongly dependent on their grain size and density, the quest to achieve simultaneously dense and fine, ultrafine, and nanostructured grain size materials has been one of the most important issues in materials science and engineering. In this work we explore novel approaches for producing dense and fine, ultrafine and nanostructured heterogeneous materials. Typical approaches consist of acoustic cavitation, high energy planetary ball milling, reaction synthesis, and shock synthesis and modified spark plasma synthesis, followed by dynamic and static consolidation and densification pre- and post-reaction synthesis. Typical heterogeneous multiphase, multi microstructural constituent materials covered in this work consist of tungsten heavy alloys, coated graphite powders, metal silicide and aluminides and ceramic composites. The synthesized and densified materials were fully characterized by OM, SEM, TEM, EDX analysis, quantitative image analysis, X-Ray diffraction and mechanical testing. This paper presents and discusses the effect of reaction and processing parameters on the microstructure, densification and strength and toughness of typical heterogeneous materials.