Processing and properties of SiC particulate reinforced Al-6.2Zn-2.5Mg-1.7Cu alloy (7010) matrix composites prepared by mechanical alloying

SIC particulate reinforced aluminium alloy (7010) matrix composites have been processed by mechanical alloying route starting from elemental powders. Proper post-consolidation by hot pressing or hot extrusion results in a fully dense composite compact that retains the fine microstructure developed during mechanical alloying. Addition of SIC was found to result in lower strengths at room temperature but higher strength at temperatures above 200 degrees C. There was nearly a 64% increase in the yield strength at 350 degrees C, brought about by addition of 20 wt.% SiC. The beneficial effects of SiC additions on mechanical strength are best realized at elevated temperatures. Fine precipitates of various intermetallics (CuAl2, Mg2Zn11, etc.) are found to be present in the solutionised and aged samples in addition to fine dispersoids of Al2O3, MgAl2O4, etc. inherited from the as-milled powders and/or formed during subsequent degassing and consolidation

Microstructural changes in a mechanically alloyed Al-6.2Zn-2.5Mg-1.7Cu alloy (7010) with and without particulate SiC reinforcement

Elemental powders of Al, Zn, Mg, and Cu (corresponding to the composition of 7010 aluminium alloy) were milled in a high-energy attritor with and without additions of SiC particulates. The microstructural changes taking place in the milled powders (which eventually lead to mechanical alloying) are found to be retarded by SiC additions. High-resolution techniques such as electron probe microanalysis (EPMA) and transmission electron microscopy/energy-dispersive X-ray analysis (TEM/EDX) revealed the presence of localized. solute-rich regions long after the diffraction line from these solutes had ceased to appear in the X-ray diffractograms, Zinc appears to be more difficult to be mechanically alloyed into aluminum than either Cu or Mg in spite of its comparatively larger diffusivity in aluminum

Crystallographic Texture Evolution of a Zinc Sheet Subjected to Different Strain Paths

The use of zinc sheets has largely increased in the last years, fundamentally because of new tendencies in architecture and, at the same time, due to its excellent properties, as corrosion resistance under aggressive climatic conditions, malleability, recyclability, and surface finishing aspect. In the present work, the X-ray diffraction technique is used to characterize the crystallographic texture evolution of a strongly anisotropic Zn20 zinc sheet (Zn-Cu-Ti) subjected to uniaxial tension, plane strain, and equibiaxial tension, for specimens cut at 0, 45, and 90 deg with respect to the rolling direction. The crystallographic texture evolution is evaluated by means of pole figures, orientation distribution function, and Kearns factors. For all tested strain paths, deformation produces a decrease in the intensity of the crystallographic textures, due to a dispersion of the orientations of the different axes around the initial maxima