Powder Metallurgy of Nanostructured High Strength Materials

Abstract

Nanostructured or partially amorphous Al- and Zr-based alloys are attractive candidates for advanced high-strength lightweight materials. The strength of such materials is often 2 – 3 times higher than the strength of commercial crystalline alloys. Further property improvements are achievable by designing multi-phase composite materials with optimized length scale and intrinsic properties of the constituent phases. Such alloys can be prepared by quenching from the melt or by powder metallurgy using mechanical attrition techniques. This paper focuses on mechanically attrited powders containing amorphous or nano-(quasi)crystalline phases and on their consolidation into bulk specimens. Selected examples of mechanical deformation behavior are presented, revealing that the properties can be tuned within a wide range of strength and ductility as a function of size and volume fraction of the different phases.

Synthesis of Nono-Crystalline Aluminum Carbide Using Thermal Treatment of Mechanically Activated Al and Graphite Mixture

“…This leads to increasing lattice strain and reducing grain size. According to XRD patterns, the graphite particles were becoming amorphous and their peaks were vanishing [8]. The phase analysis of the samples milling for 40 h shows the broadened peaks of Al, which are consequence of the high rate of the crystallite size reduction as well as increase the lattice strain.…”

Synthesis and characterization ofin situnanocrystalline intermetallic phase reinforced AlTiSi amorphous matrix composite

“…Among the various possibilities, hot/warm pressing or extrusion is a possible method to fabricate bulk samples from mechanically alloyed powders [19][20][21][22]. Sintering at high temperature and pressure proves counter-productive due to the tendency for crystallization of amorphous matrix or grain growth of the nanostructured aggregate.…”