Tensile tests of rolled sheets of a 5083 Al alloy were conducted between -196°C and 200°C and microfractographic observations were made on an electron microscopy.
(1) A yield phenomenon occurred except at 200°C. Further, serrated flows were prominent at room temperature and 100°C.
(2) Elongation to fracture was minimum at 100°C. At -196°C, uniform elongation contributed to the total elongation, while at 200°C local elongation mainly contributed to it.
(3) From a high notch yield ratio and a small notch tensile ratio at -196°C, it was inferred that the 5083 alloy was sensitive to the stress concentration and tended to retard the crack propagation or the void growth after yielding.
(4) Although dimple patterns were observed on the fracture surfaces of specimens tested at every tempera- ture, laminated cracks were also present at -196°C. The depth of the dimples was 5 to 20μ and became smaller at -196°C.
(5) There were cleaved inclusions at the bottom of the dimples. Multiple cleavage fracture of inclusions was observed at -196°C.
(6) EPMA analyses showed that the inclusions at the dimple bottoms were mainly Al-Fe-Mn compounds while most inclusions at the dimple edges were Mg-Si compounds.

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The pressure distribution along width direction in cold rolling of Al sheets with different initial orientations were measured by the pressure pick-up pin method. The pressure distribution depended on the initial orientation or the rolling texture. It became a flat or a convex pattern even when the flat pattern was usually observed in the commercial Al sheets. However, when the sheets had been produced from the soaked slabs through hot and cold rolling, the pressure distribution became insensitive to the initial orientation and could be classified by the unified classification. The P.M.F. (Pressure Multiplication Factor) corresponded to high, medium and low potential rolling textures. The result of the present study can be used to estimate the pressure distribution of the sheets which have mixtures of several different orientations.

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Conditions for the pore formation in an Al-4%Cu alloy were examined by the unidirectional solidification technique. Gas pressure in pores and negative pressure due to solidification contraction were calculated from the gas content, and the quantity of pores with the metallographic method. Main results obtained were as follows:
(1) Gas pressure in pores was 2 to 5 atms at the pore formation temperature.
(2) Initial gas content required for gas pore formation increased with an increase in solidification rate. When there was not enough gas for pore formation, a shrinkage pore was formed.
(3) When the solidification rates were 3, 6, 12, and 60cm/hr, the negative pressures were 1, 1.5, 2 and 5 atms respectively.
(4) The critical gas content for pore formation was approximately 0.15cc/100g.

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The effect of gas on the tensile properties of a unidirectionally solidified Al-4%Cu alloy was studied. Gas content, porosity, pore distribution and pore types were controlled by changing the melting and solidification condition. The results obtained are as follows:
(1) Tensile strength of pore free sound samples, obtained by solidification in argon, increased as the solidification rate increased. Thus, it was inferred that the dendrite spacing influenced the tensile strength.
(2) When samples were solidified in vacuum, shrinkage pores were formed perpendicular to the tensile direction and the tensile properties became inferior. Melting and solidification in air produced gas pores, which did not affect the tensile properties.
(3) The directionality of the cast fiber structure affected the tensile properties. Tensile test pieces, cut at some angles to the growth direction, showed the worst tensile properties, especially when vacuum solidification was employed.

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The basal slip of Mg3Cd single crystals was studied in the disordered and the ordered states. Results obtained are as follows:
(1) The ordered specimens were very brittle and showed pronounced serrated flow.
(2) In the disordered state CRSS depended on temperature below -78°C, while in the ordered state it scarcely depended on temperature.
(3) CRSS at 20°C increased from-1.3kg/mm² in the disordered state to-5.0kg/mm² in the ordered state.
(4) Slip lines in the disordered state were straight, coarse and distributed rather uniformly, while in the ordered state they diffused and localized.
(5) In the disordered specimens dislocations arranged as pile-up arrays on the basal plane, and few dislocations on the nonbasal planes were observed. While, in the ordered specimens superlattice dislocations were observed on the basal plane where the dislocation density was low, however dislocation tangles consisting of unit dislocations on the basal and nonbasal planes were observed where the dislocation density was relatively high.

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