Influence of plastic deformation on occurrence of discontinuous precipitation

Some observations on deformation-related discontinuous precipitation in an Al-14.6at.%Zn alloy

“…A comparison of the fraction transformed among the samples cold-rolled to various degrees together with an undeformed sample is given in Table 1. In agreement with a previous work [12], metallographic examination revealed plastic strain to be heterogeneous with localized deformation bands prominent in the cold-rolled specimens. The polarized light micrograph in Fig.…”

“…This suggests that the ␤ phase is most likely a product of heterogeneous grain boundary nucleation and, in this respect, the resulting structure might be interpreted as indicative of a discontinuous product, for the early-stages of discontinuous reactions typically involve the formation of precursor grain-boundary nuclei of the solute-rich phase. However, the duplex equiaxed nanostructure developed is not the lamellar configuration typical of DP in such an alloy system at conventional grain sizes [12,18,19] and, while it has developed under conditions in which DP would be expected, it may not be readily classified as a conventional discontinuous product in morphological terms.…”

“…It has attracted considerable interest [1][2][3] over the last three decades with regard to both initiation and growth mechanisms and transformation kinetics. There has, in particular, been a considerable amount of research effort devoted to investigation of the discontinuous precipitation in alloys subjected to prior plastic deformation [4][5][6][7][8][9][10][11][12]. There is a common view that the strain energy associated with either local or general plastic deformation may impart a driving force for the migration of grain boundaries [13] that is complementary to the contribution from chemical free energy.…”

“…Deformation substructures, such as dislocations and deformation bands, which occur more regularly in deformed alloys, may also lead to diverse precipitation behaviours. While it is generally believed that continuous precipitation occurs preferentially in association with dislocations and deformation bands, and compete thermodynamically to suppress DP development [1,6,12], it has been suggested that deformation bands may serve as nucleation sites for DP [16]. In contrast, the enhanced DP development within cold-deformed surface layers of Ni-In [7] and Cu-Ag [8] alloys has been attributed to recrystallization in advance of DP.…”

Study of the non-isothermal microstructural evolution of deformed Cu–15 wt.%In and Cu–9 wt.%Sb alloys by means of X-ray diffraction and dilatometry

“…During heat treatment of deformed supersaturated solid solutions, recovery, precipitation and recrystallization are favorised, generating complex interactions [1,2]. Hence, several works on these reactions have been carried out.…”