Annealing-Induced Hardening in Ultrafine-Grained and Nanocrystalline Materials

Research output: Contribution to journalReview article

2 Citations (Scopus)

Abstract

Annealing of deformed metals is considered as a process necessarily leading to softening due to the annihilation of lattice defects. However, in ultrafine-grained (UFG) and nanocrystalline materials, annealing at moderate temperatures may induce hardening. This review summarizes those effects that can result in annealing-induced hardening (AH) in fine-grained materials. It is noted that only those hardening phenomena are considered as AH effects that are not accompanied by the change of the phase composition and/or the grain size. Therefore, herein, strengthening caused by precipitation is not discussed. It is shown that heat treatment of nanomaterials can cause hardening due to the relaxation of grain boundaries and segregation of alloying elements to the grain boundaries as these effects hinder the occurrence of grain boundary sliding. For UFG metallic materials processed by severe plastic deformation techniques, the annihilation of mobile dislocations and the clustering of the remaining dislocations into low-angle grain boundaries during annealing can yield hardening. It is also shown that plastic deformation after annealing can cause a restoration of the yield strength and hardness to the same level as observed before annealing. The possible reasons of this deformation-induced softening effect are discussed in detail.

Original languageEnglish
Article number1900507
JournalAdvanced Engineering Materials
DOIs
Publication statusPublished - Jan 1 2019

Fingerprint

Nanocrystalline materials
hardening
Hardening
nanocrystals
Annealing
annealing
grain boundaries
Grain boundaries
softening
plastic deformation
Plastic deformation
Grain boundary sliding
Crystal defects
causes
Alloying elements
yield strength
Ultrafine
Dislocations (crystals)
Nanostructured materials
Phase composition

Keywords

  • annealing-induced hardening
  • dislocations
  • grain boundaries
  • nanocrystalline materials
  • segregation

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Annealing-Induced Hardening in Ultrafine-Grained and Nanocrystalline Materials. / Gubicza, J.

In: Advanced Engineering Materials, 01.01.2019.

Research output: Contribution to journalReview article

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