—序言作者曾经研究过 AI-4%Cu 合金的疲劳行为与时效组织之间的关系,但如果根据这个研究成果,则可知含有 G.P.(I)区或θ″相试样的疲劳强度与含有θ′相的试样的相比,在高应力下较好,而在低应力下却下降。并且这个现象可认为是由下列原因造成的:在前者的试样中由于 G.P.(I)区或吉θ″相与位错的相互作用产生了贯穿晶内的尖锐的直线状滑移带,沿滑移带容易产生裂纹及其扩展,在后者的试样中由于 - Preamble The author has studied the relationship between the fatigue behavior of AI-4% Cu alloys and aged tissue, but based on this finding, it can be seen that the fatigue strength of specimens containing GP (I) or θ “ ’Phase of the sample, it is better under high stress and lower under low stress, and this phenomenon can be considered as the result of the following reasons: In the former sample due to GP (I) or Kyrgyzstan θ ”phase and dislocations generate a sharp linear slip band throughout the crystal and easily cause cracks and spread along the slip band. In the latter sample, due to the