Influence of cutting parameters on the ductile-brittle transition of single-crystal calcium fluoride during ultra-precision cutting

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• 作者：Xiao Chen ; Jianfeng Xu ; Haisheng Fang…
• 关键词：Ultra ; precision cutting ; Critical depth of cut ; Single ; crystal calcium fluoride ; Fracture toughness
• 刊名：The International Journal of Advanced Manufacturing Technology
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：89
• 期：1-4
• 页码：219-225
• 全文大小：
• 刊物类别：Engineering
• 刊物主题：Industrial and Production Engineering; Media Management; Mechanical Engineering; Computer-Aided Engineering (CAD, CAE) and Design;
• 出版者：Springer London
• ISSN：1433-3015
• 卷排序：89

文摘

The cutting mode transition from ductile to brittle is related to the depth of cut for the machining of brittle materials. The critical depth of cut for ductile to brittle transition (DBT) during single-point diamond turning of single-crystal calcium fluoride was examined, and the effect of cutting direction, cutting speed, and tool rake angles were investigated. Results show that the cutting speed had a slight effect on the critical depth of cut for DBT, while negative rake angle tools yielded large critical depth of cut for DBT. The influence of cutting direction (crystallographic orientation) on the critical depth of cut for DBT was associated to fracture toughness (K_C) of the materials. Higher K_C values induced larger critical depth for DBT. Furthermore, periodic variations of K_C values as a function of the crystallographic orientation correlated well with changes in critical depth ranging between 100 and 600 nm. This resulted in the successive emergence of brittle and ductile cutting regions when a nominal depth of cut of 0.5 μm was used, while it led to the formation of a smooth and homogenous surface with R_a of 2.838 nm at a nominal depth of cut of 0.1 μm.