Investigation of microstructures of laser surface-treated Zr702 sheet using electron channeling contrast imaging and electron backscatter diffraction techniques

摘要: Abstract In this paper, specimens cut from a fully recrystallized Zr702 sheet were surface-treated by pulsed laser at two different powers (200 and 50 W) their microstructures investigated electron channeling contrast imaging backscatter diffraction techniques. For both the laser-treated specimens, three modified zones with distinctly microstructural features are presented surface to substrate: melting zone (MZ), solid state phase transformation (SSPTZ) essentially unaffected base metal zone. The MZ is completely comprised of α plates while SSPTZ could be further divided into SSPTZ-1 SSPTZ-2, according cooling mainly β α + β domains, respectively. With decreasing power, modification depth mean width decrease. Detailed characterization on suggests that plate structures (MZ SSPTZ-1) in 200 W 50 W produced diffusion diffusionless transformation, those untransformed grains SSPTZ-2 spite maintained bulk morphologies, slight subdivisions subgrains found inside them due extensive dislocation activities induced stresses and/or recovery.