Engineering grain structure in metals through on-line laser ultrasonic imaging

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Materials used in performance engineering (e.g. metals and alloys) are made up of crystals (or grains) and the size, orientation and distribution of these crystals, the arrangement of these crystals plays a significant role in determining the material characteristics. Controlling this distribution will provide a useful way to ensure the properties of the materials made match the design requirements.This project will integrate a surface acoustic wave ultrasound imaging technique with a laser powder bed fusion system. The experiments will allow the direct linking of the production parameters with the immediate change to the material grain distribution. This will enable control of the grain distribution with in parts to be controlled so the properties of the material can be varied spatially to optimise performance.This will be investigated using a custom spatially resolved acoustic spectroscopy rig integrated with an Aconity PBF machine. It will register the acoustic image of the previous layer with the build strategy on subsequent layers to control the distribution (and orientation) of the grains.