Novel Joining Methods for Titanium and Nickel Superalloys

Dear Colleagues,

Titanium alloys and nickel superalloys are integral to the efficient operation of modern gas turbines. Gas turbine component designs are continuously developing, with more complex parts being introduced into service.

Along with increased performance, there can be drawbacks that come with implementing complex geometrical components, such as an increased difficulty in repairing these components. Indeed, the ability to repair engine components provides engine manufacturers with a significant opportunity to reduce costs through reduced material replacement and a reduction in time off-wing.

Some of these structures may be large scale, which offers both challenges and opportunities for repair. Component geometry must be retained post repair while adjacent temperature sensitive regions may need to be protected. Advanced materials also provide challenges in repair, where higher integrity material properties are required. Component replacement has a considerable effect on costs, accounting for up to 70% of engine maintenance costs.

Examples of joining methods that may be used as repair processes for titanium alloys include fusion welding techniques such as tungsten inert gas (TIG) welding, plasma arc (PA) welding, laser beam (LB) welding and electron beam (EB) welding.

Conventional joining methods, such as friction welding, have proved difficult for new generation nickel-based superalloys; therefore, there is much interest in emerging and novel joining technologies for these alloys.

Indeed, novel joining methods with the potential to offer high integrity joints at relatively low cost, while providing opportunities to salvage otherwise redundant gas turbine components, are of considerable interest to aeronautic and other industries.

In this Special Issue, we aim to provide a wide set of articles covering novel joining and repair methods for nickel and titanium alloys. It is hoped that this open access issue will provide a place for readers to familiarize themselves with both conventional and more innovative joining methods frequently used for the joining and repair of aero-engine alloys.

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Metals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• Joining
• Bonding
• Nickel alloys
• Titanium alloys
• diffusion bonding
• fatigue
• fracture
• EBSD
• grain boundary engineering
• texture
• facets
• mechanical