QUANTITATIVE XCT EVALUATION OF POROSITY IN AN ALUMINUM ALLOY CASTING

摘要

Traditional destructive sectioning and NDE techniques including radiography and ultrasound provide insufficient 3D qualitative and quantitative porosity diagnostics, characterization, and visualization capabilities. Improved methods are required for efficiently assessing the detailed nature, extent and distribution of porosity in research, product development, prototyping and first-items manufactured inspection stages of engineering materials and structures. One quite powerful and recent NDE modality that has been demonstrated to be most advantageous in the 3D diagnostics of volumetric porosity is industrial x-ray computed tomography, XCT. With this non-invasive approach, very large numbers of irregular shaped pores can be individually characterized according to voxel or object spatial coordinates, surface area, pore volume, aspect ratio, and size distributions. In addition, virtual transparency and pseudo-color image processing techniques permit the 3D visualization of all pores in-siru within the object casting. Examples of such porosity characterization and the cognitive visualization of same using the XCT modality in a representative aluminum casting are presented and discussed.