Deformation of metals and alloys has been found to be related to initial solidification phenomenon. But the deformation mechanism of them, especially alloys, has not been clear yet. This study aims at finding differences in the deformation mechanism between pure metals and alloys. Low melting point metals such as Bi, Pb, and Sn and low concentration alloys of these metals were melted and dropped on a chill plate in order to measure the deformation. The deformation of pure metals decreases with alloying. The process of the deformation was directly observed using a high speed camera to find the relation between the beginning time of deformation and the amount of deformation. The deformation is found to be large if the beginning time is short, and small if the beginning time is long. The deformation of alloys is proportional to the temperature gradient at the beginning of deformation like that of pure metals.

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  To study the formation mechanism of banded segregation in centrifugal casting, molten Al-4.4%Cu alloys were poured into a stainless drum, and the casting was tilted from 10 to 30 degree to cause the shear deformation in the solid-liquid coexisting region. Banded segregation formed for the equiaxed structure but not for the columnar structure. The fraction solid of the place where banded segregation formed was between 0.2 and 0.3 at the start of tilting. The banded segregation formed when the fraction solid gradient was above 0.05mm^-1 and tilting speed of the drum above 50mm/s. Copper concentration was 5.1 to 5.5% in the banded segregation, which is larger than that in the neighboring fine equiaxed zone (4.1 to 4.8%). The development of dendrite structures was observed in the banded segregation. The boundary between the banded segregation and neighboring zone was not clear. It has been concluded that slip developed due to the shear deformation in the solid-liquid coexisting region from gravity force, and the slip region was filled with solute rich liquid, thus resulting in the banded segregation. A similar phenomenon can be expected in centrifugal casting.

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  In order to examine the formation mechanism of the double composite layer which occasionally forms in the Al-transition metal alloy pipes produced by Centrifugal Duplex Casting, a model experiment named “Injection Quenching” has been executed. In this experiment, a hyperperitectic Al-Cr alloy melt (the jet melt) was injected into a molten aluminum (the bulk melt) to be cooled rapidly. The primary intermetallic compound particles sedimented to the bottom of the mold. The mixed alloy was furnace-cooled, and was quenched at a given temperature to freeze the distribution of the primary particles. The obtained results are summarized as follows : (1) The primary particles crystallized with “copious nucleation” in the jet melt constitute the fine composite layer. (2) After the formation of the fine composite layer, floating particles dispersed in the bulk melt grow and pile up on the fine composite layer to constitute the coarse composite layer.

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  Age-hardening processes were investigated on pure Al-Si-Cu and Al-Si-Cu-Mg alloys containing about 7mass%Si, 2.72 to 4.08mass% Cu and 0 to 0.47mass%Mg and also on a commercial JIS-AC4B alloy by using a TEM, Vickers macro hardness tester and EPMA. A series of alloy specimens were solution treated at 773K for 10h, and subsequently aged at 433K and 473K for 10min to 10⁴min. The typical hardness-aging time relations are obtained for each alloy specimen. Age-hardnening occurs faster in the Al-Si-Cu-Mg and AC4B alloys than in the ternary Al-Si-Cu alloy. The maximum hardness of the specimen aged at 433K increases from HV95 to HV152 as the Mg content of the alloy increases from 0 to 0.43mass%. TEM shows the high density dislocations distributing around the eutectic Si particles which are expected to have formed in the α phase during quenching from the solution-treatement temperature, because of the difference in the coefficient of thermal expansion between the α matrix and eutectic Si. The formation of the GP Zone is suppressed and the precipitation of θ’ is promoted in the ternary Al-Si-Cu alloy which contains higher density dislocations. A number of tiny particles of the Mn-rich compound precipitate in the α matrix of the solution-treated AC4B alloy, which decreases the Cu content of the α phase and the age-hardening ability of the AC4B alloy.

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  In order to clarify the effects of matrix structure and stress ratio (mean stress) on the fatigue limit of spheroidal graphite cast irons, axial loading fatigue tests were carried out under the conditions of stress ratio R = -1, 0.1 and 0.5 on four kinds of spheroidal graphite cast irons with different matrix structures. In the case of pearlite and ausferrite (bainite) structures, the fatigue limit can be estimated with high accuracy by the equation proposed by Y. Murakami et al. , which is capable of calculating the fatigue limit from Vickers hardness and defect size based on fracture mechanics procedure. In the case of ferrite and ferrite + pearlite structures, it can not be estimated by the same equation, and the estimated values were about 15% lower than the fatigue limit determined by S-N curves. The fatigue limit decreases with the increase of the stress ratio and that at an arbitrary stress ratio can be estimated by the modified Goodman diagram.

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  Several problems not seen in conventional casting processes are encountered with the evaporative pattern casting process. A major one occurs when the foam pattern is evaporated by pouring molten metal. The pyrolysis of poly (methyl methacrylate) foam patterns by molten metal produce methyl methacrylate, carbon monoxide, carbon dioxide and unburned hydrocarbons, and possibly small amounts of benzene. These volatile pyrolysis gases are harmful and released during metal casting using foam patterns. Consequently, caution must be exercised when handling these gases. Handling and disposal guidelines of these gases should also be developed at each site of use for the preservation of natural environment. This paper reviews some analysis data on the pyrolysis gases of foam patterns and their countermeasures in the evaporative pattern casting process.

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