7. Conclusion

At the end of this article, it seems appropriate to recall a few key issues concerning material selection. The variety of available materials, processing methods and required performance levels make material selection one of the most difficult problems encountered by the engineer when designing an industrial product. It is imperative to consider the problem of selection at every stage of the design process, and not to deprive oneself by habit or ignorance of the innumerable possibilities of choice. But to do this, it is necessary to have, on the one hand, the conceptual tools to compare materials objectively (this is the meaning of the performance index method we have presented here) and, on the other hand, data on materials at the right level of precision and generality that corresponds to each stage of the selection procedure. Recent years have seen the development of computerized databases...