Silicon carbide mirror blank materials were characterized using ultrasound phased array technology to
determine the feasibility of using this method for rapidly characterizing material homogeneity and locate anomalous
flaws. A 10MHz 64 element linear probe was used to measure and image the top and bottom surface reflected signal
peak amplitudes. C-scan images located the presence of possible sub-surface heterogeneities as well as surface scratches
invisible to the eye. Bottom surface scans located variations in homogeneity within the sample bulk. High frequency
ultrasound phased array was found to be well suited for detailed characterization of SiC mirror blanks.
Silicon carbide (SiC) high energy mirrors from M-Cubed, Schafer Corp, Poco and Trex Inc. were investigated using nondestructive
ultrasound C-scan imaging. Reflected signal amplitude variations from the top surface of the SiC mirrors
were imaged to locate surface and subsurface inhomogeneities. Where possible, the bottom surface reflected signal
amplitude and material velocity were mapped to evaluate bulk properties. Elastic property mapping was also performed
on a dense SiC mirror sample to look for regional variations in Poisson's ratio, Young's modulus, shear modulus, and
bulk modulus. These ultrasound techniques were successfully utilized for detection of subsurface inhomogeneities in the
SiC mirror samples.