FIGURE 1.4 Progress of critical temperature of the best superconducting material as a function of time.

K.Rapid progress in developing materials with even higher transition temperatures culminated in the present (1988) record of 125 K (Figure 1.4). This discovery not only is of great scientific interest, but it also promises to have a significant practical impact in a wide range of fields. The technical difficulties that prevent the general use of these materials today are precisely those connected with synthesis and processing that contribute the principal challenge to materials science and engineering as a whole.

  • Scientists and technicians improved the transparency of silica glass slowly over the centuries from 3000 B.C. to 1966, when work on optical fibers was begun in earnest. Today, these fibers are some 100 orders of magnitude more transparent than they were in 1966 (Figure 1.5). A single glass fiber 0.01 mm in diameter can transmit thousands of telephone conversations—many more by far than can be sent over a conventional cable.

  • Even for abrasives and cutting tool materials, it is possible to find significant, often exponential increases in the performance of materials. Figure 1.6 shows, for example, that cutting tool speeds have increased by a factor of 100 since the turn of the century, owing to the development of new



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