Principle Investigator: Dr. John PattenResearch Assistants: Saurabh R. Virkar and Thomas

Kremenski

Dr. Vitali Prakapenka examines a DAC

sample.

Argonne National Laboratory –Advance Photon Source

Synchrotron Facility in Chicago

At the heart of the experimentation was the diamond anvil cell (DAC). In order to simulate the stresses of machining, our specimen had to be subjected to pressures up to 100 GPa with temperature exceeding 2000˚ K by laser

Diamond Anvil Cell

The Diamond Anvil CellLaser Beam for heating the sample

Laser Beam for heating the sample

•To duplicate the pressure and temperature encountered during SiC machining

•To study the phase transformation at high pressure and temperature

•To better understand micro-laser machining process (µ-LAM)

Powder for 4H SiC in 150 µm tip diamond Powder of 4H SiC in 300 µm tip diamond Powder of 6H SiC in 150 µm tip diamond IPG Laser 100 W

Phase transition in 4H SiC at 66 GPa and 1550 K temperature Phase transition in 6H SiC at 88GPa and 1550 K temperature

Before Phase transition in 4H SiC After Phase transition in 4H SiC

X-ray diffraction pattern before (black line) and after phase transformation (pink line) in 4H SiC

Before phase transformation in 6H SiC

After phase transformation in 6H SiC

X-ray diffraction pattern before (black line) and after phase transformation (pink line) in 6H SiC

Data Analysis TEM of the sample µ- Raman to analyze the absorption at high pressure Assembly of Diamond Anvil Cell for next test