The influence of temperature and grain boundary volume on the resistivity of nanocrystalline nickel

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms The thermal stability and modes of recrystallisation of nanocrystalline nickel has been observed through a conduction-based non-destructive test. Resistivity measurements have been utilised to quantify grain boundary volume fraction and microstructure. This observation makes clear the distinction of the factors that contribute to resistivity and demonstrates that these contributions are related to microstructure, either directly or in-directly. In static systems, the contribution of ordered grains and low-order grain boundary atomic arrangements in small grained material has been measured and correlated with resistivity. Measurements of in-situ resistivity conducted at high temperature gives changes with time which are related to grain growth, during heat treatment. This shows that resistivity can be used as a technique for observing the microstructure and grain growth of small grained material. V C 2015 AIP Publishing LLC.

In-Situ Monitoring of Phase Transition and Microstructure Evolution in Ni-Based Superalloys by Electrical Resistivity: Direct Comparison With Differential Scanning Calorimetry and Application to Case Studies

“…In addition, repeated heating of PX superalloys did not change resistivity at super solvus temperatures as shown in Figures 8, 10, and 11 although grain growth was observed in a sample after multiple heating cycles. In fact, grain boundary effect appears only if a grain size is below 100 nm, [22] which is by far smaller than grain size of PX superalloys used in this study. Therefore, compositional effects of all alloys can be directly compared using extrapolated resistivity at 1300 °C, which does not show a clear relationship between the alloy composition and the resistivity.…”

“…It has been used to assess material properties in different metallic systems such as Al, Ti, and Zr alloys. [18][19][20][21] In the case of Ni-based superalloys, it can be used to characterize grain growth, [22] volume fraction of the c¢ phase, [23,24] and dissolution and precipitation kinetics of c¢ phase. [24,25] However, electrical current can accelerate recovery and recrystallization, and it can, in principle, affect the phase transformation process in metallic materials.…”

“…[26][27][28] Several studies have made attempts to extract microstructural information from Ni-based superalloys through electrical resistivity measurement. [22,23,25,[29][30][31][32][33] Other studies directly compared DSC and resistivity for analyses of physical properties, but data on superalloys are particularly limited. [19][20][21]34,35] Overall, the analyses so far have been limited to specific and fundamental uses, and there is a need for comprehensive understanding to make the best use of this method.…”

Influence of heat treatment on the microstructure and tensile properties of Ni-base superalloy Haynes 282

“…7and (8) the total volume fraction is used throughout, since it represents the average spacing [38], so it is not necessary to separate the individual volume fractions corresponding to imagined continuous grain boundary g' film. From this, the volume fraction of grain boundary g' can be estimated for a given grain size, with radius R, according to [49]…”

Hydrogen sorption capacity of crystal lattice defects and low Miller index surfaces of copper

“…A similar situation occurs for Ni [11], and the authors suggest further that for Ni, the grain boundaries (GBs) are sites where the segregation of bulk absorbed H can occur. Some GBs are defects with excess volume which can create internal surfaces prone to binding H-atoms [12,13]. For Cu, internal surfaces such as those present in vacancies and vacancy clusters lead to segregation of H from the bulk interstitial nondefective sites [3, 4, 8-10, 14, 15].…”