Powder extrusion, which is based on the superplastic behavior of Zn-22%A1 eutectoid alloy, was proposed to reduce the forming load and promises to provide fine microstructures in the manufacture of miniature helical g...Powder extrusion, which is based on the superplastic behavior of Zn-22%A1 eutectoid alloy, was proposed to reduce the forming load and promises to provide fine microstructures in the manufacture of miniature helical gears. The specifications of the helical gears were as follows: module, 0.3; number of teeth, 12; and helix angle, 15°. Compacted powders were consolidated by sintering and solution heat treatment. The consolidated billets consisted of lamellar and fine-grained microstructures. Extrusion experiments were carried out under the following conditions: temperature, 250 ℃; strain rates, 2.36× 10-3 s^-1 and 1.18× 10^-1 s-1. The mechanical properties of the extruded helical gears were investigated by measurement of the Vickers hardness and extrusion load, and by scanning electron microscopy.展开更多
基金Project (2010-0008-277) supported by the NCRC (National Core Research Center) Program through the National Research Foundation of Korea,funded by the Ministry of Education,Science,and TechnologyProject (NRF-2009-K20601000004-09E0100-00410) supported by PNU-IFAM JRC
文摘Powder extrusion, which is based on the superplastic behavior of Zn-22%A1 eutectoid alloy, was proposed to reduce the forming load and promises to provide fine microstructures in the manufacture of miniature helical gears. The specifications of the helical gears were as follows: module, 0.3; number of teeth, 12; and helix angle, 15°. Compacted powders were consolidated by sintering and solution heat treatment. The consolidated billets consisted of lamellar and fine-grained microstructures. Extrusion experiments were carried out under the following conditions: temperature, 250 ℃; strain rates, 2.36× 10-3 s^-1 and 1.18× 10^-1 s-1. The mechanical properties of the extruded helical gears were investigated by measurement of the Vickers hardness and extrusion load, and by scanning electron microscopy.