Effect of Aging on the Ballistic Performance of AA-7017 Alloy

Abstract

This study presents the effect of aging on microstructure, texture, mechanical and ballistic properties of AA-7017 aluminium alloy. AA-7017 alloy is subjected to three different aging namely under-aging, peak-aging and over-aging. Significant difference is observed in the mechanical properties after aging. The alloy exhibits maximum strength and hardness in the peak-aged condition. From texture measurements, it is noticed that the overall intensity of orientation distribution function increases from under-aged to peak-aged condition. The AA-7017 aged plates are impacted with 7.62 mm steel core projectiles at 820±10 m/s to evaluate the ballistic performance. It is noticed that AA-7017 alloy displays best ballistic resistance in peak-aged condition. Distorted material flow lines and adiabatic shear band induced cracking is detected in post ballistic microstructure. The ballistic performance of AA-7017 alloy is correlated with the variations in the microstructure and mechanical properties with aging


(a) True stress-true strain curves; Variation of (b) Strength (c) Hardness (d) % Elongation (e) Charpy impact toughness with aging and (f) log (true stress) vs. log (true plastic strain) curves of AA-7017 alloy at different aging conditions.
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(a) Aged plates after ballistic impact.
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SEm images: (a) Intermetallic particles aligned in the rolling direction, (b) Intermetallic particles aligned in the shear flow direction in deformed ASBs, (c) Absence of bigger intermetallic particles in transformed ASBs, (d) Close view of the centre region of transformed ASBs, (e) Bifurcation of ASBs in PA and oA specimens, and (f) Cracks originating from deformed ASBs.
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Heat treatment schedule for different aging conditions
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