The aerospace industry relies on continual improvements in the performance of materials to achieve reduced life cycle costs. Total aircraft structural weight reductions of around 8% per decade have been achieved since the 1970’s, contributing to commercial aeroplane fuel burn reductions of about 1% per year over the same period.
Ilika and Boeing have recently collaborated on an investigation of high entropy alloys to establish if this class of materials offers promising structural phases which merit further investigation and if high-throughput thin films techniques are comparable to the standard bulk approach. The programme chose quinary alloys of iron, nickel, cobalt, copper and gallium around the equiatomic composition. The alloys were made in thin film form using Ilika’s high throughput platform, compositionally characterized before being annealed at 700°C and then structurally characterized with X-ray diffraction before a final compositional check was made. The high throughput work was carried out in a two-month period. In that period 2548 systematically varying compositions were made and characterized. As a result, a clear understanding of the compositional dependence of the formation of the four distinct phases was gained, including the percentage occurrence of each bcc and fcc phase within the quinary compositional spread. Finally, some bulk samples were prepared using traditional ingot preparation methods for selected compositions, which gave equivalent results to the thin film alloys.
Further details of some of the work undertaken in this collaboration have been published in this paper:
The Minerals, Metals & Materials Society (2015) High-Throughput Synthesis and Characterization of Thin Film High Entropy Alloys Based on the Fe-Ni-Co-Cu-Ga System, in TMS2015 Supplemental Proceedings, John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9781119093466.ch138
Print ISBN: 9781119082415
Online ISBN: 9781119093466