Decision Science-Driven Assessment of Ti Alloys for Aircraft Landing Gear Beams

Titanium alloys, with their low density, exceptional mechanical properties, and outstanding corrosion resistance, play a vital role in various aerospace applications. Our decision science-driven assessment focused on metastable <i>β</i>, near-<i>β</i>, <i>α</i> + <i>β</i>, and near-<i>α</i> Ti alloys for landing gear applications, integrating multiple-attribute decision-making (MADM) methods, principal component analysis (PCA), and hierarchical clustering (HC) is based on current literature. The ranks of the alloys evaluated by diverse MADM methods were consistent. The methodology identifies five top-ranked Ti alloys assists and verifies the guidelines for alloy design. The top-ranked alloy, Ti1300-BM-nano-α (alloy chemistry: Ti-5Al-4V-4Mo-3Zr-4Cr, solution treatment: 800 °C for 1 h followed by air cooling—solution treated below <i>β</i> transus, and aging: 500 °C for 4 h followed by air cooling), stands out with a percentage elongation (<i>%EL</i>) ~3.3 times greater than the benchmark or goal (density, <i>d</i> = ~4.6 g/cm³; yield strength <i>YS</i> = ~1250 MPa; <i>%El</i> = ~5), while maintaining similar density and yield strength. The analyses underline that metastable <i>β</i> Ti alloys comprising globular primary <i>α</i> + trans <i>β</i> matrix coupled with <i>α</i> precipitates in trans <i>β</i> are the base optimal microstructure to fine-tune using thermomechanical processing for aircraft landing gear applications.