Critical Cutting Condition for Brittle-Ductile Transition of KDP Crystals in Ultra-Precision Machining

Jing He Wang; Ming Jun Chen; Shen Dong; H.X. Wang; J.H. Zhang; Wen Jun Zong

doi:10.4028/www.scientific.net/KEM.329.409

Paper Titles

A Study on Deformation and Removal Mechanisms of Tungsten Carbide Using Nanoindentation
p.385

Material Removal Mechanisms Involved in Rotary Ultrasonic Machining of Brittle Materials
p.391

Numerical Simulation and Prediction of Surface Heterogeneity in Diamond Turning of Single-Crystalline Germanium
p.397

A Finite Element Analysis of Stress Fields in Vickers Indentation on Brittle Materials
p.403

Critical Cutting Condition for Brittle-Ductile Transition of KDP Crystals in Ultra-Precision Machining
p.409

Nano-Structures Fabrication by Laser Combined with Near-Field Scanning Optical Microscopy
p.415

Ceramic Grindability Evaluation with PCA Method
p.421

Analysis of Mechanical Property of Crystal KDP and Simulation of Ultra-Precision Cutting Process in the Ductile Mode
p.427

Experimental Investigation of Brittle to Ductile Transition of Single Crystal Silicon by Single Grain Grinding
p.433

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Critical Cutting Condition for Brittle-Ductile Transition of KDP Crystals in Ultra-Precision Machining

Abstract:

In this paper, mechanical characteristics of KDP crystal anisotropy are analysed theoretically. Vickers indentation experiments are adopted to validate the variation rule of hardness and fracture toughness in different orientation of KDP crystal plane (100), and a model to calculate critical cutting thickness of brittle-ductile transition is proposed for the KDP crystals. The result shows that, on the crystal plane (100), the minimum value of critical cutting thickness of KDP crystal in brittle-ductile transition appears in the direction [110], but the maximum appears in the direction [010]. Finally, the ultra-precision machining of KDP crystal is performed, and the results agree well with the theoretical conclusions. Super-smooth surface with a roughness RMS of 6.6nm is reached as machined in the crystal direction [010], and 11.2nm to the direction [110].