• 文献标题:   Fracture, fatigue, and sliding-wear behavior of nanocomposites of alumina and reduced graphene-oxide
  • 文献类型:   Article
  • 作  者:   WANG Q, RAMIREZ C, WATTS CS, BORREROLOPEZ O, ORTIZ AL, SHELDON BW, PADTURE NP
  • 作者关键词:   alumina, grap he ne, toughnes, fatigue, wear
  • 出版物名称:   ACTA MATERIALIA
  • ISSN:   1359-6454 EI 1873-2453
  • 通讯作者地址:   Brown Univ
  • 被引频次:   4
  • DOI:   10.1016/j.actamat.2019.12.035
  • 出版年:   2020

▎ 摘  要

There is growing interest in using 2D graphene-related reinforcements to toughen brittle ceramics in nanocomposites. However, there is a lack of fundamental understanding of the toughening mechanisms and microstructural effects in such nanocomposites. To address this paucity, fully-dense nanocomposites of aluminum oxide (Al2O3) matrix and reduced graphene-oxide (rGO) reinforcements (similar to 5 vol%) of different average-thicknesses and orientations are fabricated and characterized. The interactions between stably propagating cracks and rGO in the Al2O3/rGO nanocomposites are observed in situ inside a scanning electron microscope (SEM). Toughening by pullout of thick rGO in the crack-tip wake in the cross-section orientation is found to be the most effective, which is consistent with the highest fracture toughness (K-IC-6.7 MPa.m(0.5)) measured in those Al2O3/rGO nanocomposites. Interestingly, upon unloading and reloading, the intact rGO crack-bridges appear to crinkle and uncrinkle without a remnant crease, respectively, which is a unique deformation property of multi-layer graphene-like materials. This points to a possible new cyclic-fatigue resistance mechanism in those nanocomposites. Sliding-wear properties of the Al2O3/rGO nanocomposites are also studied, where the hardness and microstructural heterogeneities are found to play dominant roles. The results from this study have implications for the creation of high-toughness, fatigue-resistant, and wear-resistant graphene-reinforced ceramic nanocomposites of the future. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.