Ultra-High Temperature Ceramic Matrix Composites
Rubio (UoB) Ultra-high temperature ceramic materials & Improvement of C/HVN low cost CMC; Apr 2014 – Mar 2016: Significant progress is being made with respect to understanding how the processing, microstructure and properties are interrelated in a 2 year leveraged programme with the Anglo-French defence company MBDA. Two related topics are being covered within the project under the Anglo-French MCM ITP initiative, Cf-UHTC powder composites and the ability to improve an existing, low cost CMC by incorporating UHTCs. The focus of the former is to determine whether the materials possess adequate properties to be used for components such as leading edges, jet vanes and engine parts in hypervelocity craft. Preparation of a prototype component is currently underway and it should be tested by spring 2016. With respect to the latter, testing is still underway, but it appears that the maximum operational temperature has been increased by several hundred degrees centigrade. The results to date for both programmes were presented at the Materials & Components for Missiles Innovation and Technology Partnership conference, held in Brighton, UK in October 2015.
Ramanujam (UoB) Ultra-high temperature ceramic structures; Jul 2014 – Jun 2016: This is a partner project to both that described for Rubio above and that for Larrimbe below. It is a 2 year leveraged programme with DSTL, which is focused on the same Cf-UHTC powder composites that is the subject of Rubio’s research. The primary focus is to determine whether the processing can be scaled up to allow the production of full size components. As a result of the project findings and working together with Rubio, a completely new impregnation technique has been developed (MBDA and DSTL are currently considering IP protection in partnership with UoB). In addition, this programme is also focusing on joining the composites to each other and to monolithics in partnership with Larrimbe below and some success has already been achieved.
Larrimbe (ICL) UHTC monoliths for supersonic applications; Jun 2014 – October 2016: This is partner project to that described for Ramanujam above. It is a 2 year project (delayed by the departure of the first postdoc to be appointed) that is focused on material development for the outer layer of a UHTC based protection system for space re-entry at very high heat flux. The goal is to find solutions to join these materials with the UHTC based composites that are the subject of Ramanuham’s research and to test and model performance. Progress is being made with respect to understanding the level and type of porosity that allows components to survive both the high heat deposited into them as well as the thermal shock associated with rapid heating and also with respect to the development of a better understanding of the degradation of the material under very high heat flux. A model is being built that allows both oxidation and melting to be predicted and good agreement between experimental observations and predictions are being achieved.
D’Angio (UoB) Processing of SiCf-SiC composites by microwave CVI; Jan 2014 – Dec 2016: This project involves a PhD student funded entirely by UoB on the topic of a fast manufacturing route to the production of SiCf-SiC composites. Using microwave chemical vapour infiltration, MCVI, as the process route, the idea is to take advantage of the inside-out heating created by using microwaves so that manufacturing times can be reduced from the current 2 – 3 months with conventional CVI to 3 – 4 days. The principle has been demonstrated and the work has led to the US Air Force agreeing to fund a 2nd PhD student, see below.
Porter (UoB) High temperature composites using microwave enhanced chemical vapour infiltration; Feb 2016 – Jan 2018: Funded by the US Air Force through the European Office of Aerospace Research & Development (EOARD), the goals are to develop an improved process for the production of SiC-based ceramic matrix composites (CMCs) via the combination of chemical vapour infiltration and microwave heating technologies and hence to educe the processing time and costs involved in the production of CMCs, whilst understanding the relationship between the full range of processing variables and the subsequent materials properties.
Paul / Ramachandran (UoB) Microwave heated chemical vapour infiltration of UHTC-based composites; Feb 2013 – Sep 2017: Focusing on the production of ultra-high temperature ceramic matrix composites, UHTCMCs, a new class of composite, this 3 year programme (end date significantly delayed by the departure of Paul and the subsequent appointment of Ramachandran) is designed to produce UHTC powder impregnated carbon fibre preforms and then to fill the residual porosity with a UHTC matrix using microwave CVI. This should yield composites with the strength and toughness of CMCs but combined with ultra-high temperature capability in terms of oxidation and ablation resistance. The equipment upgrade needed is now largely complete and the research itself has begun.