A Comparative Study of Cryorolling and Cryo-Cross Rolling Treatment on Tensile and Fracture Properties of Al 5052 Alloy

In present study, Al 5052 alloy was cross rolled at cryogenic temperature up to a true strain of 2.3. The impact on microstructure, mechanical, and fracture behaviour is then examined. The microstructure is characterised through optical microscopy and TEM, which shows the formation of ultrafine-grained (UFG) structure in cryo-cross rolled (CCR) samples. Reduction in grain size of CCR samples leads to improvement in tensile properties as a direct consequence of the Hall–Petch effect. As the UFG structure is formed, CCR samples demonstrate a simultaneous increment in tensile strength and fracture toughness compared to solution treated (ST) samples and high dislocation density formed during cryo-cross rolling. The conventional rolling at a cryogenic temperature known as cryorolling (CR) was also performed on Al 5052, and the results were compared with CCR. CCR samples revealed higher ductility enhancement from 7.38% to 10.64% for all sample conditions with respect to CR samples because of the change in strain path and recrystallized microstructure. Due to higher dislocation density, the CCR sample indicates higher hardness from 112 to 128HV as compared to CR sample.