Zn-22 Al alloy closed-cell foams were fabricated by melt foaming process using hydride foaming agent. The compressive properties were investigated under quasi-static condition. The structure of the foamed material was...Zn-22 Al alloy closed-cell foams were fabricated by melt foaming process using hydride foaming agent. The compressive properties were investigated under quasi-static condition. The structure of the foamed material was analyzed during compression test to reveal the relationship between morphology and compressive behavior. The results show that the stress-strain behavior is typical of closed-cell metal foams and mostly of brittle type. Governing deformation mechanism at plateau stage is identified to be brittle crushing. A substantial increase in compressive strength of Zn-22 Al foams was obtained. The agreement between compressive properties and Gibson-Ashby model was also detected.展开更多
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
In this paper, the superplastic characteristics of a 15 SiC(vol. pct) whisker reinforced Zn-22AI alloy composites, fabricated by low pressure infiltration and solute treatment after extrusion with the extrusion rate o...In this paper, the superplastic characteristics of a 15 SiC(vol. pct) whisker reinforced Zn-22AI alloy composites, fabricated by low pressure infiltration and solute treatment after extrusion with the extrusion rate of 10:1, was investigated. The result showed that the composite exhibited a tensile elongation of 150% and a strain rate sensitivity value of about 0.33 at the initial strain rate of 6.67×10-2 s-1 and at 658 K where an appropriate amount of liquid phase was presented in the composite.展开更多
文摘Zn-22 Al alloy closed-cell foams were fabricated by melt foaming process using hydride foaming agent. The compressive properties were investigated under quasi-static condition. The structure of the foamed material was analyzed during compression test to reveal the relationship between morphology and compressive behavior. The results show that the stress-strain behavior is typical of closed-cell metal foams and mostly of brittle type. Governing deformation mechanism at plateau stage is identified to be brittle crushing. A substantial increase in compressive strength of Zn-22 Al foams was obtained. The agreement between compressive properties and Gibson-Ashby model was also detected.
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.
文摘In this paper, the superplastic characteristics of a 15 SiC(vol. pct) whisker reinforced Zn-22AI alloy composites, fabricated by low pressure infiltration and solute treatment after extrusion with the extrusion rate of 10:1, was investigated. The result showed that the composite exhibited a tensile elongation of 150% and a strain rate sensitivity value of about 0.33 at the initial strain rate of 6.67×10-2 s-1 and at 658 K where an appropriate amount of liquid phase was presented in the composite.
