Kilpatrick, W, Brown, D, McMurray, R and Leacock, AG (2010) The effect of serrated yielding on the determination of r-values in aluminium alloys and yield locus calibration. Materials Science and Engineering: A, 527 (29-30). pp. 7557-7564. [Journal article]
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This study investigates the effect serrated yielding (Portevin-Le Châtelier effect) has on the determination of the plastic strain ratio (r-value) for the 2024 aluminium alloy. The aluminium alloy specimens were initially in the fully annealed O-condition. The specimens experienced a softening mechanism through a solution heat treatment (SHT) process, followed by an oil quench. The specimens were permitted to recover for periods ranging between 0.5 and 12 h by room temperature (RT) natural ageing before undergoing a uniaxial tensile test along the longitudinal axis to determine the r-value as a function of natural ageing time. The current study reveals the irregular variation in the transverse strain affects the gradient of the longitudinal–transverse strain plot and consequently the r-value. It is demonstrated that the serrated yielding directly influences the Hill 1948 yield locus when calibrated using two r-values and one yield strength for the 2024 aluminium alloy. Serrated yielding results in an underestimation of the plane stress (rolling) of 0.5 ≤ plane stress rolling (MPa) ≤ 5.6, plane stress (transverse) of 1.0 ≤ plane stress transverse (MPa) ≤ 9.2, and biaxial stress of 1.4 ≤ biaxial stress (MPa) ≤ 7.4. It is also shown that serrated yielding occurs after a critical strain of 0.07 ≤ plastic strain ≤ 0.13 and is reduced by natural age hardening.
|Item Type:||Journal article|
|Faculties and Schools:||Faculty of Computing & Engineering|
Faculty of Computing & Engineering > School of Engineering
|Research Institutes and Groups:||Engineering Research Institute|
Engineering Research Institute > Advanced Metal Forming
|Deposited By:||Dr Alan Leacock|
|Deposited On:||12 Sep 2012 10:51|
|Last Modified:||12 Sep 2012 10:51|
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