This study was made on the content of iron in solid solution, the amount and type of intermetallic phases in Al-Fe alloys solidified in a wide range of cooling rate. Al-0.04%Fe, Al-0.10%Fe, Al-0.25%Fe, Al-0.55%Fe, Al0.10%Fe-0.04%Si and Al-0.55%Fe-0.12%Si alloys were cast into a wedge-shaped aluminum mould, a castiron mould and as and mould. Thus a wide range of cooling rate during solidification could be obtained. The measurements of cooling rate, dendrite arm spacing, iron content in solid solution and identification of secondary constituents were carried out by thermal analysis, electric resistometry, optical microscopy, electron microscopy and X-ray diffraction. The dendrite arm spacing in the ingots cast by several industrial casting processes were also measured.
The results obtained are summarized as follows:
(1) The relation between the dendrite arm spacing D(μm)and the cooling rate C (°C/sec) was determined as D×C^0.33=33.4
(2) As cooling rate increased the content of iron in solid solution increased. At a constant cooling rate, increasing addition of iron increased supersaturation of iron in solid solution.
(3) Supersaturation of iron was reduced by addition of silicon.
(4) Al₃Fe, Al₆Fe and Al_mFe (a new body-centered tetragonal Al-Fe phases⁶⁾) were identified as secondary constituents. These were found to be formed in the following ranges of cooling rate:
Al₃Fe: less than 1°C/sec
Al₆Fe: from 1 to 10°C/sec
bct AlmFe: more than 10°C/sec.
(5) By using the above relation, cooling rates for several industrial casting processes were estimated:
200-700°C/sec for Hunter engineering process
20-80°C/sec for pressure die casting
0.5-20°C/sec for D. C. cast
0.5-13°C/sec for Properzi process
0.1°C/sec for book mould casting
0.01°C/sec for shell mould casting.
Estimation of iron content in solid solution and existing intermetallic compounds could be also made for Al-Fe alloys cast by these casting processes.

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The formation of Mg₃Cd superlattice has been studied on a Mg-25.2at% Cd alloy by means of X-ray diffraction and transmission electron microscopy. Specimens were initially quenched from the disordered state, 180°C or quenched from the two phase region and then isothermally annealed at 50, 70 and 80°C.
The results obtained are as follows.
(1) The change in degree of order with the quenching temperature was measured. The critical temperature for ordering in this alloy was 155°C.
(2) The change of degree of order and domain size in specimens quenched from the disordered state were determined. The domain size determined from the X-ray diffraction method well corresponded to that from the transmission electron microscope method. The activation energy for ordering determined from the relaxation time was found to be0.87eV.
(3) When quenched from a temperature between 155°C and 140°C, broadening in the fundamental line (0002) occurred, which would result from the coexistence of the ordered and disordered phases. While, a very broadened line from the disordered phase overlapped on the superlattice line (1011) when annealed. The separation of (0002) and (1011) lines into two isolated ones arising from the ordered and disordered phases was made using the Gauss equation. The degree of order in the ordered phase was close to unity in the quenched state and little change was observed by annealing. While the degree of order in the disordered phase changed as in the case when annealed after quenching from the disordered state.
(4) When annealed after quenching from the two phase region, growth of ordered phase particles in the disordered phase was observed by means of the transmission electron microscope.

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The effect of manganese addition up to 0.5wt% on the aging behaviour of an Al-4.2wt%Cu alloy was reexamined. The solubility of manganese in the ternary alloy at the solution treatment temperature was about 0.3wt%, without loss of copper in solution. With further addition of manganese, a gradual decrease of copper in solution resulted. The initial rate of room temperature aging observed by electrical resistivity measurements was not materially affected by the amount of manganese. However, retardation of age hardening occurred with increase of manganese content, and in an alloy containig 0.5wt% manganese no effective hardening occurred during a few weeks.
Within the temperature range of artificial aging at which hardening occurred in two stages, the peak hardness of the ternary alloys was vertually unaffected by the amount of manganese and it was higher than that obtained for the binary alloy with the same copper content, though in alloys with higher manganese content, the retardation of hardening was apparent at the initial stage of aging at all temperatures. As raising the aging temperature to where hardening occurred in a single stage, the peak hardness decreased gradually followed by a marked drop. The higher the manganese content, the lower was the peak hardness. In alloys containig lower manganese content, the age hardening effect was remarkable at 180200°C in comparison with the binary alloy of the same copper content.

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The authors have studied on the drilling machinability of aluminum cast alloy AC8B, and in this paper, analytical experiments are described on the effects of lip-height difference of a drill, ΔH on the cutting phenomena and the drilling accuracy.
The results obtained are as follows;
(1) The cutting process of drilling with a drill having a lip-height difference can be devided into three stages. In the first stage, the revolving axis coincides with that of a drill, whereas in the second stage, it coincides with that of a chisel. In the third stage, the revolving axis moves from the chisel axis to the drill axis.
(2) From the geometry of the cutting edge, the relation between the enlargement of the drilled hole, Δd and the value of ΔH is shown as Δd = ΔHtanθ/2. According to the experimental data obtained, the measured values agree well with the calculated ones.
(3) Astrong correlation was found between the value of ΔH and the net cutting torque. It increased with increase of ΔH.

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