Study of precipitation and deformation characteristics of the aluminium-lithium alloy by X-ray double crystal diffractometry

The X-ray double crystal diffractometry technique was utilized to follow the ageing and deformation characteristics in the aluminium-lithium (Al-Li) alloy. This non-destructive method is extremely sensitive to measure the strain and dislocation density within individual grains through X-ray rocking curves. For ageing at 200 ° C, optimum ageing needed for maximum hardness was 32 h. Dislocation multiplication was responsible for reduction of hardness beyond 32 h ageing. In addition, when the specimen was deformed in tension, both compressive and tensile residual strains were found within individual grains.