Decision science-driven assessment of magnetocaloric materials for thermal management systems

The two essential benefits of All-Electric-Aircraft (AEA) are reduced carbon emissions and maintenance. A critical challenge in AEAs is thermal management: batteries are difficult to cool because of the narrow and low optimal temperature range of high performance. A need for sustainable materials for thermal management systems is imminent. Magnetic Cooling (MC) reveals the highest Performance and Energy Conversion Efficiency Coefficient among various cooling technologies. MC utilizes magnetocaloric materials (MCMs) that heat up when exposed to a magnetic field and cool down when the field is removed―the cyclic exposure to and shielding from a magnetic field creates a heat pump. The MCMs are a diverse class of materials, including but not limited to transition metal-based amorphous materials, rare-earth-based amorphous materials, rare-earth-containing crystalline materials (e.g., laves phases, etc.), and rear-earth-free crystalline materials (viz., Heusler alloys, etc.) synthesized/fabricated by a myriad of techniques. Materials Informatics-enabled materials discovery and selection, popularly termed Materials 4.0, is enabled on the existing big data of synthesis, processing, modeling, characterization, and properties of diverse MCMs to identify novel MCMs for AEAs. A novel methodology that combines multiple-attribute decision-making (MADM) methods, principal component analysis (PCA), and hierarchical cluster analysis (HCA). Weights of the properties (or attributes) were evaluated by objective (Shannon's entropy method) and subjective methods. The rank assigned by several MADMs, viz., Technique of order preference by similarity to ideal solution (TOPSIS), Grey Relational Analysis (GRA), Operational competitive ratio (OCRA), and so forth, were consistent. PCA and HCA consolidated the MADM ranks and grouped similar alloys. The investigation highlights similarities across several MCMs, suggests potential replacement or substitute for existing MCMs, and provides directions for improvement and/or development of sustainable MCMs for thermal management systems.