The design, fabrication, and testing of a centrifuge for laser materials processing under enhanced gravity conditions

A simple, cost-effective centrifuge for use in an enhanced gravity laser materials processing system was developed. This system is capable of producing an acceleration normal to the sample surface ranging from 2g_e to 10g_e Design constraints include a maximum resultant acceleration of 10g_e and a beam delivery system which is capable of using either a CO₂ or Nd:YAG laser system as the energy source. The available process diagnostics include photodiodes, thermocouples, a CCD camera, and accelerometers in three axes.

An experiment was run to test the system and determine the effect of gravity on the weld pool shape by performing spot welds in Inconel 718 at effective g levels ranging from 2g_e to 10g,sub>e at 2g_e intervals. Post-process metallurgical analysis was performed to determine the shape of the weldment.

The results of the experimental data indicate that gravity seems to play a slight role in the size and shape of partial penetration welds; however, differences between results for cw data and ccw data also indicate the possibility of a coriolis effect.