| Title |
A Study on the Fabrication of Al - Pb Bearing by Gas Atomization and Spray Forming |
| Authors |
양영석(Y . S . Yang); 박신성(S . S . Park); 정철민(C . M . Jung); 허태녕(T . Y . Huh); 성장현(J . H . Sung); 정은(E . Jung) |
| Abstract |
Spray Forming technology has been developed at the Department of Materials Science and Engineering, Univ. of Ulsan, for the fabrication of tube, billet and plate of Al-12%Pb alloys. Spray Forming Process involves atomizing a stream of molten metals and collecting the droplets on a substrate before they have solidified, The effects of geometry(orifice diameter and tip design) and position of the metal delivery orifice in atomization device on the pressure characteristics at the tip of orifice have been studied. Mathematical model has been developed to predict the velocity and temperature profiles of the droplets as a function of their flight distances. Microstructural characteristics of Al-12%Pb hyper-monotectic alloys by spray forming process were examined. Dense (~99. 4%) material with fine-grained equiaxed microstructure was spray-formed using nitrogen as the atomizing gas. It was found that lead(Pb) particles existing in the microstructure were homogeneously distributed in the aluminium matrix and along the grain boundaries. The shape of lead particle were approximately spherical and the mean particle size was about 3-4㎛. |