Research on Materials for High Power Laser Windows
Quarterly technical rept. no. 2, 1 Aug-31 Oct 1972
MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR MATERIALS SCIENCE AND ENGINEERING
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The mechanical properties of polycrystalline alkali halides have been investigated. The effects of texture, surface preparation, and coatings have been shown to significantly effect the stress-strain characteristics samples with strengths over 5000 psi and with considerable ductility have been prepared. The plane strain fracture toughness has been measured and indicated a factor of 3.5 improvement in the resistance of crack propagation. The KIC values for polycrystalline KCl were 943 psi.in. to 12 power compared to 272 psi. in. to 1 2 power for the single crystal. Flaw detection, fractography, and laser damage studies have also been initiated. Studies of thin film coatings of Ge, MgF2, and NaF on polycrystalline KCl have continued. Double salt crystals of barium chloride-potassium chloride were grown for optical absorption measurements. The IR absorption edge occurs at 14 micrometers.
- Lasers and Masers