抄録
Al-4 mass%Cu alloy was melted in a quartz tube with a small nozzle at the bottom. By pressing the melt surface with argon gas pressure of 0.12 to 0.13 MPa, the alloy melt flowed out through the nozzle onto the copper substrate and was rapidly solidified. A rectangular tube specimen was formed by moving the sub. strate in the X-Y horizontal directions and downwards simultaneously.
With increasing the moving speed of the substrate, the thickness of one layer deposited reduced and the spacing between eutectics in the interdendritic regions increased, while the width of the castings remained almost constant. With increasing the number of layers, the cooling rate was decreased, and the weldability between the layers improved. Under optimum conditions, a coexisting solid-liquid region was formed between the layers, resulting in smooth side surface of the castings due to the surface tension of the liquid phase in the region.
