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Ductile to Brittle Transition of 4H-SiC


Project Time Frame: January 2005 – April 2006 

Material: 4H Single Crystal Silicon Carbide (SiC)

Project Aim: To establish a Ductile to Brittle Transition (DBT)/critical depth of cut for the material with a specifically defined cutting direction and crystal orientation.

Project Description: Silicon carbide, like other brittle materials, is known for its poor machinability. However, ductile-regime machining is possible under certain conditions. This can be achieved if machining occurs at depths less than the critical depth of cut. Beyond this value, a Ductile-to-Brittle Transition (DBT) occurs and the material behaves in a brittle-fracture manner. The purpose of this research is to determine the DBT for a single-crystal 4H-SiC wafer by performing Nanometric cutting (Nanocuts) experiments. The depth of cut is adjusted over a range of 100nm to1000nm in order to cover the entire ductile to brittle-regime and the corresponding material removal behavior. The Nanocuts were carried out using the Nanocut II, a second generation prototype experimental machining instrument. The Nanocuts were imaged and measured using an Atomic Force Microscope (AFM) and the height profile from the scanned images was used to determine the DBT.

Related Publications:

“Ductile to Brittle Transition of a Single Crystal 4H- SiC Wafer by Performing Nanometric Machining” – ISAAT 2007, Precession Grinding and Abrasive Technology at SME International Grinding Conference.View

Related Presentations:

2007 ISAAT-SME International Precision Grinding and Abrasive Technology Conference View