The relations between steady state creep rate, ε_s, and temperature, T, stress, σ, internal stress, σ_ath, or effective stress, σ_th, were investigated with a stress dip technique in the strain rate from 10^-4 to 10^-2/sec between 300°C and 500°C. The results obtained are as follows:
(1) ε_s is expressed as ε_s = A₁σⁿ exp (-Q/RT), where A₁ is a constant, n the stress exponent -4.7) and Q the activation energy for creep, equal to 35kcal/mol.
(2) σ_th and σ_ath are, respectively, related to σ in the expression, σ_th = A⁴σ^1.3 exp (-Q'th/RT) and σ_ath = A₃σ^0.77 exp (σ'_ath/RT), where Q'_th and Q'_ath were 3.1kcal/mol and 2.6kcal/mol, respectively. The ratio of Qath to σ decreases with an increase of stress and decreases with temperature when it is from 0.3 to 0.6.
(3) ε_s is also related to σ_th and σ_ath; ε_s = A₂σ_th^3.6 exp (-Q_th/RT) and ε_s = A₃σ_ath^6.1 exp (-Q_ath/RT), where Q_ath and Q_ath are 24kcal/mol and 51kcal/mol, respectively. The discrepancy between the activation energy for self diffusion, Q_SD, and Q_th is accounted for by considering the temperature dependence of the mobile dislocation density. The difference between Q_th and Q_SD can also be explained by assuming that the average spacing between dislocations at subboundaries dereases with an increase in temperature.

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The phase diagram, mainly in the Al corner, of the Al-θ-Cd system was studied by electrical resistivity and lattice spacing measurements, thermal analysis and microscopic observation. In addition, the solubility of Cu in Al with 0.02 to 0.3wt% Cd was determined. The results obtained are as follows:
(1) The θ-Cd alloys in the Al-θ-Cd system was considered as a pseudo-binary system. It was concluded that this system had a monotectic reaction expressed as L₁_??_L₂ + θ at 580°C.
(2) The monotecto-eutectic reaction of the Al-θ-Cd system, L₁_??_L₂ + Al + θ, occurred at 544°C. This nonvariant reaction was characterized by 27wt%Cu, 18wt%Cd and the rest of Al.
(3) The isothermal cross sections diagram at 520°C showed that the addition of Cd had little effect on the solubility of Cu in the Al-Cu-Cd alloy.
(4) It was suggested that aging suppression in Al-Cu-Cd alloys was not explained by assuming significant decrease of Cu content in the solid solution of Al.

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In relation to several industrial problems to encounter the application of the boehmite coating, the Auger electron microscopy was utilized to analyze the elements on the surface of aluminum which had been immersed in several kinds of boiling water. A scanning electron microscope (SEM) and an infrared reflection spectrometer (IRRS) were also used. AES confirmed that Si, Ca and Fe existed in the discolored surface layer. The decrease and disappearance of Fe Auger electrons corresponded to those of discoloring. Thus, Fe was responsible for discoloring as well as Si and Ca. From the IRRS and SEM study, it was found that when boehmite coating was sufficiently produced, discoloring did not develop. Discoloring was prevented by adding sodium aluminate and chromic anhydride to water; addition of sodium aluminate accelerated formation of boehmite while that of chromic anhydride did not produce any trace of boehmite. It was found that discoloring disappered when the once discoloredsurface was immersed in boiling deionized water or was heated in air.

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Binary aluminum alloys (Al-2.0wt%Si, Al-0.4wt%Cr, Al-0.2wt%Fe and Al-1.7wt%Mn) were solidified unidirectionally and quenched into oil to study the solid-liquid interface. Following results were obtained:
(1) The curvature of the planar interface of the Al-Si alloy is larger than that of the other alloys. This suggests that the interface of the Al-Si alloy has different characteristics from that of the other alloys. In the Al-Cr alloy, there is a banded zone which shows a trace of the movement of the interface during quenching.
(2) The mean diffusion coefficients of solutes in the liquid have the tendencies identical to those in the solid, except Mn which diffuses rapidly in the liquid. The calculated diffusion coefficients are 9.7 × 10^-5cm²/sec in the Al-Si alloy, 2.7 × 10^-5cm²/sec in the Al-Mn alloy and 1.3 × 10^-5cm²/sec in the Al-Fe alloy.
(3) The solute distribution coefficients at the solid-liquid interface are close to the equilibrium coefficients.

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Cantilever shearing tests and dry orthogonal low speed cutting tests were conducted on commercially pure aluminum (1100) plates. Shearing mechanisms were considered from the residual strain observation near a tool tip with a moire strain measuring method. In shearing tests, the compressive strains were present in the H-materials, while the tensile strains remained in the O-materials. When the O-material was sheared, the compressive strain developed in front of a tool tip. However, when the tool tip passed through, the sign of the strain reversed and the tensile strain remained on the shear plane. When the O-materials were tested in orthogonal cutting, the strain in the cutting direction was compressive in front of the tool tip. It changed the sign near the tool tip and became tensile strain on the cutting plane, because of the tensile deformation in the backward region of the tool tip. The extent and hardness of the deformed layer increased under the shearing and cutting condition which increased the residual strain.

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