Deformation behavior and joining of a MgF2 optical ceramic

✍ Scribed by C. Lorenzo-Martin; D. Singh; J. Johnson; J.L. Routbort

• Book ID: 104022692
• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 687 KB
• Volume: 27
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2007.02.187

✦ Synopsis

Compressive deformation behavior of a polycrystalline magnesium fluoride (MgF 2 ) ceramic was investigated at temperatures ranging from 760 to 830 • C in an argon atmosphere at strain rates between 2 × 10 -6 and 4 × 10 -5 s -1 . Steady-state flow stresses increased with increasing strain rates and ranged between 2 and 38 MPa. Stress exponents of ≈1.4 ± 0.2 were determined at temperatures >760 • C, indicative of a viscous diffusioncontrolled deformation mechanism. Activation energy, determined from flow stress as a function of temperature, at a constant strain rate, was ≈476 ± 60 kJ/mol. Self-joining by plastic deformation of MgF 2 was demonstrated at 830 • C at a strain rate of 5 × 10 -6 s -1 . The joined samples were characterized by optical transmission measurements and their transmittivity was ≈80% of the unjoined sample in the 2.5-8 m wavelength range.