title: Crack propagation and the material removal mechanism of glass-ceramics by the scratch test.
abstract: To eliminate the negative effects of surface flaws and subsurface damage of glass-ceramics on clinical effectiveness, crack propagation and the material removal mechanism of glass-ceramics were studied by single and double scratch experiments conducted using an ultra-precision machine. A self-manufactured pyramid shaped single-grit tool with a small tip radius was used as the scratch tool. The surface and subsurface crack propagations and interactions, surface morphology and material removal mechanism were investigated. The experimental results showed that the propagation of lateral cracks to the surface and the interaction between the lateral cracks and radial cracks are the two main types of material peeling, and the increase of the scratch depth increases the propagation angle of the radial cracks and the interaction between the cracks. In the case of a double scratch, the propagation of lateral cracks and radial cracks between paired scratches results in material peeling. The interaction between adjacent scratches depends on the scratch depth and separation distance. There is a critical separation distance where the normalized material removal volume reaches its peak. These findings can help reduce surface flaws and subsurface damage induced by the grinding process and improve the clinical effectiveness of glass-ceramics used as biological substitute and repair materials.
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, 300072 China. Electronic address: qiuzhongjun@tju.edu.cn.
authors.forename: Zhongjun
authors.initials: Z
authors.lastname: Qiu
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, 300072 China.
authors.forename: Congcong
authors.initials: C
authors.lastname: Liu
authors.affiliation: School of Dentistry, Hospital of Stomatology, Tianjin Medical University, Tianjin, 300070 China.
authors.forename: Haorong
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, 300072 China.
authors.forename: Xue
authors.initials: X
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, 300072 China.
authors.forename: Fengzhou
authors.initials: F
authors.lastname: Fang
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, 300072 China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Tang
mesh_terms: D002516:Ceramics; D005898:Glass; D008422:Materials Testing
keywords: Crack propagation; Glass–ceramics; Material removal mechanism; Scratch tests