State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, 300072, China.
State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, 300072, China.
J Mech Behav Biomed Mater. 2021 Sep;121:104617. doi: 10.1016/j.jmbbm.2021.104617. Epub 2021 Jun 1.
To reduce the surface flaws and subsurface damages of glass-ceramics as clinical substitute and repair materials, it is necessary to clarify the material removal behaviors and crack propagation modes in the grinding process. In this paper, a multi-tip indenter tool was fabricated and assembled on a Nanomechanical testing system. The experiments of ramp load scratching with the single-tip/multi-tip indenter tools were conducted on glass-ceramics to compare the material removal behavior under different scratch methods. The surface morphology, subsurface cracks propagation, and the brittle-ductile transition region were observed and investigated. Based on the scratch experiments, the finite element simulation model was established to analyze the stress characteristics in the glass-ceramics. The result shows that in multi-tip scratches, as the depth of scratch increases, the growth of surface cracks mainly takes three forms. Compared with non-instant multi-scratch, instant multi-scratch makes the propagation path of lateral cracks closer to specimen surface, suppresses the propagation severity of lateral and median cracks, and increases the depth of brittle-ductile transition region. This paper's results provide a fundamental understanding of multiple abrasive grains instant interaction on the material removal mechanism, and help to improve the clinical performance of glass-ceramics as biomedical materials.
为了降低玻璃陶瓷作为临床替代和修复材料的表面缺陷和亚表面损伤，有必要阐明磨削过程中的材料去除行为和裂纹扩展模式。本文制作了一个多尖端压头工具，并将其组装在纳米力学测试系统上。采用单尖端/多尖端压头工具进行了斜坡载荷划痕实验，以比较不同划痕方法下的材料去除行为。观察和研究了表面形貌、亚表面裂纹扩展和脆性-延性转变区。基于划痕实验，建立了有限元模拟模型来分析玻璃陶瓷中的应力特征。结果表明，在多尖端划痕中，随着划痕深度的增加，表面裂纹的生长主要有三种形式。与非瞬时多划痕相比，瞬时多划痕使侧向裂纹的扩展路径更接近试样表面，抑制了侧向和中间裂纹的扩展严重程度，并增加了脆性-延性转变区的深度。本文的结果提供了对多磨粒瞬时相互作用对材料去除机制的基本理解，有助于提高玻璃陶瓷作为生物医学材料的临床性能。
