Mechanical Engineering / Sustainable Energy Session:

Title:           Age hardening and cold deformation assisted aging treatment on the characteristics of quartz powder reinforced stir-cast aluminium-zinc alloy metal matrix composites
Authors:      S. S. Sharma, Jagannath K., ChandrashekharBhat, U. AchuthaKini, P. Raghavendra Prabhu, Jayashree P. K., Gowrishankar M. C.
Abstract:     Mankind has been aware of composite materials since several hundred of years before Christ and has applied innovations to improve the quality of life. Contemporary composite material resulting from research and innovation from the past few decades have progressed from fiber glass to automobiles bodies to particulate composites for aerospace and range of other applications. Composites are the gifted twenty first century aterials primarily fabricated to meet the stringent demands of high specific strength, high resistance to wear and good toughness. Modern composites constitute an important class of design and weight efficient structural materials which cover every sphere of engineering life. The heat treatment of Al-Zn alloys composites consists of conventional age hardening and cold deformation i.e. rolling assisted age hardening (low temperature thermomechanical treatment). Al – Zn alloys with a small addition of magnesium or copper reinforced with particulate materials are used in aerospace industries. Copper or magnesium improves wettability. The resistance offered by the particulate reinforcement for the moving dislocations impart strain hardening. Cold deformation increases lattice defects, which in turn improves the mechanical properties. In view of this, five different Al – Zn alloy composites reinforced with pure quartz powder (Sio2), 120 microns (2 wt. %, 4 wt. %, 6 wt. % and 8 wt. %) are prepared by conventional stir casting process. The cast alloys are age hardened with solutionising and aging as two basic steps. The solution treated alloys are cold rolled to increase the lattice defects. The hardness, strength and toughness values are analyzed and compared with quartz free Al – Zn alloys. Higher peak hardness and strength are the characteristics of cold rolled and aged samples.

Keywords:   Particulate, Reinforcement, Dislocation, Hardness, Aging, Solutionising
Pages:         360-364

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