Papers by Keyword: Semi-Solid Forming

Abstract: Near net shape forming of Al-Al3Fe functionally graded materials (FGMs) have been studied. FGM billets fabricated by a centrifugal method were extruded under the condition of a mixture of molten Al eutectic and solid Al3Fe particles. Both distribution and profile of Al3Fe particles were characterized by and the variation of volume fraction of Al3Fe particles was observed. Shore hardness of the Al matrix was also measured to evaluate the strength of the FGM before and after the semi-solid forming associated with the character of distributed Al3Fe particles. It was confirmed that Shore hardness increased with increasing the volume fraction of Al3Fe particles and after the semi-solid forming than before. This was due to the fact that Al3Fe particles after the semi-solid forming became fine by shear stress introduced by liquid Al flow.

Abstract: The parts manufactured by die casting process usually contain liquid segregation and porosities. To solve these problems, the semi-solid forming process has been applied. The process enables material in the semi-solid state to be completely filled, and parts with the complicated shape to be fabricated by applying relatively low pressure. This process is necessary in order to control the microstructure of the billet as well as to achieve the desired semi-solid billet state. In this study, a horizontal high-frequency induction heating device which can be fabricated by semi-solid forming irrespective of a billet's size was developed. A globular structure of the reheated billet and a billet's temperature distribution during the reheating process for A356 were investigated.

Abstract: The microstructures and electrical conductivity of newly developed Cu-Ca alloys for semi-solid forming have been investigated. High purity calcium was added to molten copper up to 1.4% by weight and mold-cast into a rod. Thermomechanical treatment (TMT) has been carried out to evaluate the variation in electrical conductivity and microstructures of Cu-Ca alloys. The electrical conductivity of copper was reduced linearly with the concentration of calcium by , where k is a constant having the values ranging from 16.7 to 20, depending on the processing condition. The introduction of prestrain significantly reduced the grain size during subsequent heating by recrystallization, influencing the electrical conductivity of Cu-Ca alloys.