Understanding temperature induced microstructural changes in additively manufactured alloys

Industry demands that material scientists and engineers continually strive to improve component performance. The mechanical strength of components is derived from the material microstructure. This microstructure changes and evolves during thermal processes.

Recent advances in additive manufacturing offer reduced component build time and machining costs but raise key questions regarding the microstructural differences between traditionally manufactured components and those produced using additive manufacturing.

This webinar explores the microstructure of both wrought and additively manufactured Titanium (Ti64), an alloy commonly used by the aerospace industry for its good fatigue resistance and high specific strength. The heating of Ti64 results in a phase change from a hexagonal closed packed crystal (hcp) structure at room temperature to the body centred cubic (bcc) phase above ~980°C, where grain growth also occurs. The duration of the elevated temperature, heating rate and cooling rate all effect the final microstructure and improved understanding of these transformations allows processing methods to be selected to form a favourable microstructure, for optimum component performance.

The microstructure evolution during these phase transformations can be measured using electron backscatter diffraction (EBSD) and modern CMOS EBSD cameras such as Oxford Instruments Symmetry detector can acquire this data at unprecedented speeds offering even greater insight into the material phase transformations.

You will learn:

•  The challenges associated with in-situ heating experiments for EBSD and how to overcome them
•  The effect heating-rate has on the high temperature recrystallisation mechanism in Ti
•  Possible links between twinning and the recrystallisation mechanism in the grain growth of high temperature Ti
•  How fast and sensitive CMOS EBSD allows the effect of cooling rates on the nucleation of the room temperature phase to be measured, and how this is related to the high temperature microstructure