金属的强度或高或低都是因为位错的存在所致。根据位错强化理论,金属可达到相当高的强度,只是因为延伸率、韧性将下降,因而限制了强韧化的程度,实用材料的强度仅为理论断裂应力的10～30%。表2列出了不含位错的“晶须”(whiskers)所具有的理论强度(强度高达10~3kgf/mm~2),但这种直径为1μm左右、长度最多为毫米级的纤 The strength of metal, both high and low, is due to the presence of dislocations. According to the theory of dislocation strengthening, the strength of metals can be quite high, simply because the elongation and toughness will decrease, thus limiting the degree of strengthening and toughening. The strength of practical materials is only 10-30% of the theoretical fracture stress. Table 2 lists the theoretical strength (up to 10-3 kgf / mm2) of whiskers without dislocations, but such fibers having a diameter of about 1 μm and a length of at most millimeters