In-situ wire direct energy deposition process development of high-performance bimetallic alloys for advanced aerospace application - PhD

We are looking for a motivated candidate to pursue a Ph.D. based on a project entitled “In-situ wire-direct energy deposition (WDED) process development of high-performance bimetallic alloys for advanced aerospace application” This opportunity arises in the field of WDED additive manufacturing, and the project aims to develop a novel process to in-situ manufacture high-quality bimetallic structures with varying geometries using WDED technique.

Compared to conventional manufacturing methods like casting and forging, the wire-based DED process offers several benefits, including reduced lead times, carbon footprint, tooling costs and material wastage, but greater design flexibility. It is attracting significant attention in industry and academia due to its ability in large-scale components production and suitability for many metal materials (e.g. steel, Ti, Al, Ni alloys). However, the application of this technique in manufacturing bimetallic components is comparatively less developed. Due to the ambient brittleness, in situ synthesis has to be utilized when using WDED in bimetallic deposition. Moreover, the layer-by-layer deposition process, coupled with the broad thermal fields produced by the heat source, exposes metallic alloys to repeated cycles of remelting and reheating. This creates a complicated interaction of various phases and microstructural elements, which may give rise to defects like cracking, as well as unfavourable anisotropic mechanical characteristics. Therefore, an in-depth process study is pivotal in realising an effective synthesis of the requisite components and the assurance of defect-free, high-performance outcomes.

The main focus of the project is to in depth investigate the melting and solidification behaviour of various bimetallic alloys with varying geometries during the in-situ WDED process and to determine and optimize the basic process parameters for producing deposits with target microstructure and mechanical properties. The overall project objectives are to: 

• Study the melting behaviour of the two base metals during in-situ deposition of bimetallic and design appropriate configurations to obtain adequate melting and solidification processes. 
• Process development of in-situ WDED for producing defects-free bimetallic structures. 
• Comparative study on the thermal behaviour, microstructural evolution and mechanical properties in the deposition of bimetallic structures with different geometries. 
• Evaluate the effectiveness of in-process mechanical work as an auxiliary means to online compensate internal stains to reduce crack tendency.

The student will be based at the Welding and Additive Manufacturing Centre. The Centre is recognised for the impact of its research into advanced fusion-based processing / manufacturing methods on industry, through extensive MSc and PhD research, and its rolling technology development programme on large-scale additive manufacturing. The WAAM programme aims to make the UK the leading technology provider in terms of transforming practice and creating a commercial option. The student will be part of a diverse and vibrant research community. In addition, an opportunity for working with the Centre’s industrial partners (e.g. GE, WAAM3D and WAAMMat) would be also provided.

The student is expected to acquire the following (including but not limited to) knowledge and skills from research in this project.

• Techniques, requirements, and applications of metal additive manufacturing and in-process mechanical work. 
• In-process data acquisition and analysis techniques. 
• Metallurgy and advanced material characterisation techniques. 
• Reviewing literature, planning, and managing research, writing technical reports and papers, presenting in meetings, conferences, and teamwork.

The successful applicant will benefit from collaborating within a diverse, multi-disciplinary team, engage directly with industry partners, and and have the opportunity to showcase their research at international conferences.

Applicants should have an equivalent of first or second class UK honours degree in a related discipline or subject area (e.g. material, mechanical and manufacturing engineering). For international students, the English Language requirement set by Cranfield University should also be satisfied. This project would suit a candidate with a genuine interest in processing and manufacturing, as well as basic understanding of metal material metallurgy and performances. Previous experience with welding or additive manufacturing is also desirable. The candidate should be self-motivated, proactive, and good at communication and teamwork.