Anisotropic Mechanical Response of Nacre to Heat Treatment Under Indentation:Effect of Structural Orientation  

作　　者：Simin Liang Yingying Li Hongmei Ji Xiaowu Li 

机构地区：[1]Department of Materials Physics and Chemistry,School of Materials Science and Engineering,Key Laboratory for Anisotropy and Texture of Materials,Ministry of Education,Northeastern University,Shenyang,110819,China

出　　处：《Journal of Bionic Engineering》2024年第3期1453-1464,共12页仿生工程学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Grant No.51902043);the Fundamental Research Funds for the Central Universities(Grant Nos.N2102002,N2102007 and N180203018);supported by the National Natural Science Foundation of China(No.52171108).

摘　　要：It is generally considered that heat treatments have a negative impact on the mechanical properties of nacre due to thermal decomposition of the organic matrix.However,the present work investigated the microindentation behavior on fresh and heat-treated nacres from two orthogonal directions,and the results demonstrate that both hardness value and damage tolerance can remain almost unchanged on the cross-section with the organic matrix degeneration,despite a significant deterioration on the platelet surface.Theoretical analyses suggest that the anisotropic response of indentation behavior to heat treatment in nacre is primarily caused by its structural orientation.Specifically,compared with a single layer of irregular interplatelet interfaces in cross-sectional specimens,the multiple layers of parallel interlamellar interfaces in in-plane specimens exhibit a much greater ability to impede indenter-triggered destruction,and heat treatments would reduce the in-plane hardness but nearly have no effect on the cross-sectional hardness.Moreover,the deeper embedding of platelets in cross-sectional specimens enhances their resistance to interface cracking caused by organic matrix degradation at high temperatures,leading to a reduced sensitivity to damage.Therefore,the indentation behavior of nacre shows different tendencies in response to variations in the organic matrix state along normal and parallel directions.

关 键 词：NACRE Structural orientation Heat treatment Indentation behavior Organic matrix 

分 类 号：Q81[生物学—生物工程]