Low temperature toughness of 30% cold rolled and annealed 5083 aluminum alloy was studied by Charpy impact test, and effect of laminated fracture on the absorbed energy was investigated experimentally. Absorbed energy measured at 77K was markedly increased by cold rolling. That increasing of the absorbed energy was due to increment in the fractured surface increased by the laminated fracture. Absorbed energy per unit area of the true fractured surface was decreased. Generation and propagation characteristics of the laminated fracture was enhanced by annealing treatment at 473K for 60ks. Laminated fracture, however, was reduced by annealing treatment at 523K or 573K. Effect of side groove was to constrain the growth of laminated cracks in the vicinity of specimen ligament. Laminated fracture was observed across the specimen ligament in the specimens with V and U-notch side groove.

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Interface reactions between CVD-SiC fibers and liquid aluminum containing Ti or Zr were investigated in a temperature range between 973 and 1273K. The reaction time ranged from 0.9 to 7.2ks. The additional elements Ti and Zr were selected because they were active in aluminum. The addition of Ti or Zr accelerated the interface reaction between fibers and the molten matrix. The element Ti was more effective than Zr to accelerate the interface reaction.

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Bond dissociation energies, ΔH, have theoretically been evaluated for the four aliphatic carboxylic acids by use of the molecular orbital method (6-31G). The calculated values of ΔH are as follows: 383kJ/mol for formic acid, 466kJ/mol for acrylic acid, 469kJ/mol for acetic acid and 480kJ/mol for propionic acid, each of which agrees well with the experimental ones. The aliphatic carboxylic acids having small values of ΔH dissociates easily. The order of the values of ΔH is in formic acid<acrylic acid<acetic acid<propionic acid, in agreement with that of values of pK_a for the acids. The values of ΔH describes that the strong acid easily dissociates the H atom in COOH group of the acids. The order of magnitude of theoretical ΔH agrees well with that of the critical electric current density for pitting corrosion initiation, I_corr, suggesting that ΔH would become a measure of degree of corrosion inhibition of the carboxylic acids.

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The effect of minor Zn alloying on corrosion resistance of Al-Li alloys (2090 and 2091) was investigated. By addition of 0.7% Zn, the SCC resistance as well as exfoliation corrosion resistance of 2090 and 2091 alloys are improved remarkably. The addition of Zn facilitates pitting corrosion and enhances general corrosion so that it suppresses selective attack in the area along the grain or subgrain boundary. This observation indicates localized corrosion on the grain or subgrain boundary is closely related to the susceptibility to SCC. Massive or film-shaped compounds with a high concentration of Zn are found on the grain boundaries in the peak-aged Zn added 2091 alloy. The precipitation of these compounds is likely to result in relieving the difference in electrochemical potential between the grain boundaries and grain bodies.

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Amorphous Al₈₈(Y_1-xCe_x)₂Ni₉Fe₁ alloys containing nanoscale fcc-Al particles have been found to exhibit tensile fracture strength (σ_f) and hardness (HV) higher than those of amorphous single phase alloys with the same compositions, without detriment to good bending ductility. The particle size of the fcc-Al phase increases in the range of 3 to 30nm with a decrease in cooling rate. The HV and Young's modulus (E) increase monotonously with increasing volume fraction of the fcc phase (V_f), while the σ_f shows a maximum in the V_f range of 5 to 26% (e.g., 1560MPa at 25% V_f for Al₈₈Ce₂Ni₉Fe₁).The increase in σ_f in the V_f range below 26% is presumably due to an enhancement of the resistance to shear deformation caused by the nanoscale fcc particles which have hardness higher than that for the amorphous phase with the same compositions. The highest σ_f for the Al₈₈Ce₂Ni₉Fe₁ alloy is much higher than that (1320MPa) for the Al₈₈Y₂Ni₉Fe₁ alloy. It is presumably a reason for this difference that the bonding force between Al and Ce atoms is stronger than that between Al and Y.

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from E_B (O-H^*) = ΔE_P-E_A (H⁺). The electron affinity of the H⁺ ion E_A (H⁺) was estimated as the same of value of ionization potential of the H atom, I_P (H) = 13.598eV. ΔE_P is the difference of E_P among the structures of II-VI; ΔE_P = E_P (II)-E_P (III, IV, V, VI). The values (in kJ/mol) obtained of E_B (O-H^*) (for the structure IV) are formic acid (527.988)>acrylic acid (490.443)>propionic acid (485.717). This order describes that the strong carboxylic acid makes its protonated acid stable and the order is the same of that of corrosion inhibition of cathodic reaction by the acids on Al. Each of the four carboxylic acids makes their protonated acids and it describes that the carboxylic acids decrease the H⁺ ion and inhibit the cathodic reaction 1/2O₂+2H⁺+2e→H₂O. This is corrosion inhibition effect on the Al cathode and the strong acid has the large effect.

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In order to find out the materials for containment of the molten Al-Li alloys and those for tools and assemblies for melting, corrosion resistance of various refractory materials to Al-Li melts has been evaluated by visual inspection, X-ray diffraction and chemical analysis. It is found that not only the advanced ceramics but also single or dual phase oxides such as Al₂O₃, Al₂O₃-MgO and Al₂O₃-SiO₂ have an excellent corrosion resistance.

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