2019 Volume 60 Issue 11 Pages 2353-2360
The paper reports the research results on precipitation hardening potentials of Al–Mn–Mg alloys containing a small amount of Cu, during aging at 150°C. The age-hardening response and phase transformation are significantly affected by the Si content of the order of 0.1%. The hardening response increases during aging with increasing Si content. The hardening potential decreases significantly by tensile deformation prior to heat treatment. The pre-strain causes an inhomogeneous nucleation of precipitation on dislocations and cell walls and restricts trans-granular precipitation during aging. In 10% pre-strained alloys, short-term aging leads to dislocation recovery, resulting in an increase in the n-value. Further decrease in dislocation density and increase in the n-value occur due to a small degree of precipitation hardening in a 0.15%-Si-added alloy, whereas dislocation recovery is suppressed by competitive precipitation in a 0.36%-Si-added alloy during prolonged aging.
This Paper was Originally Published in Japanese in J. Japan Inst. Light Metals 68 (2018) 473–479.
