ICME-based Design of HSHC Cu-alloys for Particle Accelerators

Remaining challenges in implementing next generation particle accelerators for high energy physics research applications include the application of new, advanced materials for resonant cavities (for accelerator and RF source) to replace the state-of-the-art material, oxygen-free high strength (OFHS) copper. Commercially available Cu-alloys have drawbacks that overwhelm the benefits if they were deployed as resonant cavity materials. This challenge requires the design of a new ultra-high vacuum compatible material with a combination of good mechanical properties (particularly high strength resistant to high accelerating gradients) and excellent conductivities (electrical and thermal) even after experiencing thermal cycles during assembly (electron beam welding or brazing at 1000℃ for hours) and bake-out stages (at 500℃ for days). In this SBIR program, QuesTek proposes to use its ICME-based Materials by Design® technology to design a high strength high conductivity (HSHC) Cu-alloy to be applied in resonant cavities for accelerators and RF sources. The ICME framework for this program is based on CALPHAD thermodynamics and kinetics modeling tools and reliable physics-based property models to link the process-structure and structure-properties relations of Cu-alloys. These tools enable the team to predict microstructure and properties of Cu-alloys, before and after the thermal processing during the assembly and bake-out stages, including ultra-high vacuum compatibility, mechanical strength, electrical conductivity and thermal conductivity. QuesTek’s ICME-based Materials by Design® approach will be utilized to optimize the chemical composition and processing routine for the newly designed Cu-alloy, complemented by testing and experimental validation. QuesTek will leverage its previous successes in the design, development, and commercialization of various novel materials/processes. The proposed Phase I project will focus on utilizing QuesTek’s proprietary models and experimental approach to design novel a HSHC Cu-alloy. Concept feasibility will be demonstrated by benchmarking property improvement (for strength and conductivity) in the designed Cu- alloy, after full thermal cycles of assembly (1000℃4 hours) and bake-out (500℃5-7 days). After demonstrating the proof-of-concept performance in the Phase I, the Phase II program will focus on improving and optimizing the developed alloy’s composition and its process routines for optimum combination of properties. The alloy will also be tested at component level, in collaboration with a manufacturer. QuesTek has extensive experience in working with various materials suppliers and processing facilities, accelerating testing and qualification for a wide range of specifications and requirements. In this program, QuesTek will work closely with subject matter experts, OEMs and end-users to develop and design the best alloys for resonant cavities.