Deformation-induced ultrafine grains near fatigue crack tip and correlative fatigue damage in Al matrix composite

New insight into the microstructural evolution and the correlative damage mechanisms near fatigue crack tip in a TiB2/Al composite was conducted by transmission kikuchi diffraction and transmission electron microscopy. It was found that the micro deformation band formed from the crack tip and ran along slip planes. Ultrafine grains were induced in deformation band, where the fatigue crack preferring to grow along these deformation-induced boundaries was first demonstrated as the essential process of crack across parent grains and grain boundaries. Ahead of crack tip, the TiB2 particles can affect crack growth by impeding the successive propagation of deformation band. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

The microstructural evolution and damage mechanisms near the fatigue crack tip in a TiB2/Al composite were investigated, revealing the formation of micro deformation bands and ultrafine grains. The study also highlighted the role of TiB2 particles in impeding the propagation of deformation bands and influencing crack growth.