Integrated multi-attribute decision-making methodology based on integrated comprehensive evaluation index: application to titanium alloy selection

Titanium (Ti) and Ti alloys are the most suitable metallic materials owing to excellent biocompatibility, corrosion resistance and specific strength for many biomedical applications. Selecting best Ti alloy is very important and practical material selection problem. Although many multi-attribute decision-making (MADM) methods are applicable, they may generate considerable differences in the results. However, it is no clarify which is better MADM. It is desirable to determine integrated result by integrating the results obtained from the individual MADMs. We proposed a new integrated MADM methodology based on integrated comprehensive evaluation index (ICEI) of candidates: ICEI-MADM. The ICEIs are the preference-weighted averages of comprehensive evaluation indices (CEIs) of candidates obtained from individual MADMs, and the preference-weights are normalized average correlation coefficients between rankings from the individual MADMs. The methodology can determine not only the integrated evaluation ranks of the candidates but also their integrated evaluation values in full consideration of the preference-weights of the individual MADMs, while the previous methods can determine only the integrated evaluation ranks without considering the preference-weights. We applied it to evaluate the comprehensive performance of 22 biomedical Ti alloys. As the result, Ti-12Mo-6Zr-2Fe (annealed) was the best Ti alloy for implant, the next was Ti-15Mo-5Zr-3Al (aged), and the Cp Ti with different grades were the worst ones. Also, the β type Ti alloys had the best performance, the α + β type Ti alloys had the moderate performance, and the α type Ti alloys had the worst performance. The methodology could be widely applied to not only biomedical Ti alloy selection but also other biomedical material selection and many MADM problems arising in practice.