Takuichi Morinaga, Masao Yamada: On the Change of various Properties of some Aluminum Alloys due to abnormal Pressure.Although a number of researchers have studied the various properties of the cast aluminum alloys at normal state, little attention has previously been given to the change of properties of them at abnormal pressure. For the purpose, a simple casting apparatus was newly devised by the authors. The specimens were obtained by our special method, have been examined by means of microscopic analyses, static and dynamic test. From the results of the experiments, the mainThe conclusion is obtained as follows: It is scarcely noticed the difference of the cooling velocity between normal and abnormal Casting, hut the rate of the latter is similar rate of the metal mold. Especially the microscopic Structures of the normal slamming were markedly changed compared with the normal slamming without a given pressure. The free crystallization of the secondary Si was suppressed by a certain critical pressure. Increasing a given pressure than that, the same structures to he modified were obtained.On the other hand, the tendency of the results of the static and dynamic test was coincide with the above said change of the structures.In a word, the modification effect was confirmed during the solidification of silumin under a critical pressure.凡ての鋳物は常気圧のもとで鋳造し，かような鋳物の諸性質については非常に良く調べられている。鋳物の欠陥となる諸因子は多くあろうが，我々の良く出合う諸欠陥は気泡，巣及び鋳造割れ等であって，以上の諸欠陥は鋳造技術の進歩改善によって或程度は除去出来るが，決して完全な除去は不可能であろう。実験室的に有効と考えられるのは，圧力を利用することで，本実験はこの意味で行ったものである
