抄録
It is commonly believed that the cause of the age-hardening of light alloy is based upon the internal strain. But we must take care to use the term “internal strain” to avoid confusion, because generally in the X-ray photograph when there exists internal strain, Debye-Scherrer rings displace or become diffuse. These Are called the first and second kind of internal strains. When light alloys are aged at room temperature, these changes in Debye-Scherrer rings do not occur. Therefore the age-hardening must not be due to these two sorts of internal strains. The hardening must be related to the dislocations in the lattice, and atoms near these dislocations are somewhat displaced from their normal position. Therefore we can say that these atoms are strained. But these strains belong to short distant type and never to the above two kinds of internal strains. So we must call this type of internal strain as the third kind. The third kind of internal strains is formed by the formations of nuclei and whether these nuclei are formed at or above the room temperature is explained by Becker's theory of the nuclear formation in solid solution. Also the cause of artificial aging due to the addition of Si is easily explained. Next, the phenomena of hardening due to aging and softening due to 'Rtickbildung. are explained as the damped oscillation in a mechanically vibrating system or as the transient phenomena in an electric circuit having electric capacity, self-inductance and resistance. And the rate of nuclear formation corresponds to the velocity of vibration or the current and the increase in the hardness to the electric quantity passed along a certain direction.
