PLASTIC-DEFORMATION MECHANISMS OF BETA-TREATED ZIRCONIUM

This study aims to determine the different deformation mechanisms of g rade 702 zirconium under uniaxial tension and at room temperature. The grade 702 zirconium tested had undergone an alpha --> beta --> alpha cycle at a slow cooling rate (similar to 15 degrees s(-1)). Three defo rmation mechanisms were identified: prismatic slip, (10 (1) over bar 2 ) [10 (1) over bar (1) over bar] twinning and (11 (2) over bar 1) [11 (2) over bar (6) over bar] twinning. The critical resolved shear stres s for prismatic slip, (10 (1) over bar 2) [10 (1) over bar (1) over ba r] twinning and (11 (2) over bar 1) [11 (2) over bar (6) over bar] twi nning was also determined. The effect of the non-uniform redistributio n of the hardening elements on location through the grain of the vario us mechanisms and on the tendency for localized deformation to develop is also discussed.