Microstructural evolution at large driving forces during grain growth of ultrafine-grained Ni–1.2wt%P

Abstract

The microstructural evolution during grain growth at large driving forces of an ultrafine‐grained Ni–1.2wt%P solid solution (starting grain size of 7nm) is evaluated for the temperature range 473 to 873 K. It is shown that the material is thermally stable as a nanocrystalline structure up to 623 K. At higher annealing temperatures the material transformed into a two‐phase Ni + Ni3P microstructure and considerable grain growth was observed. The Ni matrix showed continuous grain growth and displayed a temperature‐dependent grain growth exponent N. The effects of driving force, grain boundary mobility, and grain boundary pinning on the final microstructure are discussed.

Nanocrystalline Ni–3.6 at.% P and its transformation sequence studied by atom-probe field-ion microscopy

“…A transformation sequence with transformation steps equivalent to steps I(a), I(b) and II of the present work has been reported for electroless plated nanocrystalline Ni±P with P contents between 3 and 13 at.% studied by dilatometry, electrical resistivity measurments, DSC, XRD, and TEM [13,14]. Two major transformation steps were also found for electrodeposited Ni±P with P concentrations from 2 at.% to the eutectic concentration of about 19 at.% by TEM [11,12] and DSC; see Ref. [8] and references therein.…”

“…Refs [8±10] and references therein. While studies of grain growth [11,12] and macroscopic properties [13] of nanocrystalline layers with lower P concentration have been published, there is less knowledge of the actual atomic-scale P distribution and its inuence on the transformation behavior [13,14].…”

Individual grain orientations and texture development of nanocrystalline electrodeposits showing abnormal grain growth

“…Furthermore, impurities cannot be held responsible for this behavior since the amount of C and S is three times higher in the material with narrow grain size distribution [2]. Additions of Fe, P and W have been proven to increase thermal stability of nanocrystalline Ni and Co electrodeposits substantially [2,[13][14][15][16]. Such chemical influences may be the reason for the occurrence of abnormal grain growth if an inhomogeneous distribution of the solutes is assumed.…”

Electrodeposited Nanocrystalline Metals, Alloys, and Composites

“…There are numerous reports of studies of the thermal stability and grain growth in electrodeposited nanocrystalline Ni, [60,107,[175][176][177][178][179][180][181][182][183][184][185][186] Ni-P alloys, [52,55,65,66,[187][188][189][190] Ni-Fe alloys, [60,107,191,192] Pd-Fe alloys, [25,193] Co, [185,194,195] Co-P alloys, [196] Ni-Co alloys, [197] and Ni-W alloys. [198] Recent reviews of the thermal stability of nanocrystalline electrodeposits are given in Refs.…”