Titanium(Ti)and nickel(Ni)elemental powders were blended by ball milling and the ball milled powders were employed to fabricate TiNi shape memory alloy(SMA)foams by spacer sintering.Effect of ball milling time on phas...Titanium(Ti)and nickel(Ni)elemental powders were blended by ball milling and the ball milled powders were employed to fabricate TiNi shape memory alloy(SMA)foams by spacer sintering.Effect of ball milling time on phase constitutes of the sintered TiNi alloy foams was studied by X-ray diffraction(XRD)analysis.Scanning electron microscopy(SEM)was used to characterize the porous structure,and compressive tests were carried out to evaluate the mechanical properties of the foams.Results indicate that porosities of the TiNi alloy foams can be controlled by using the spacer sintering method,and the porosities show a significant effect on the mechanical properties and shape memory effect(SME).展开更多
Fabrication characteristics are unstable in direct foaming method. Therefore, most of near net-shape metallic foams are produced, and investigated by powder metallurgy. Direct foaming method, however, has many benefi...Fabrication characteristics are unstable in direct foaming method. Therefore, most of near net-shape metallic foams are produced, and investigated by powder metallurgy. Direct foaming method, however, has many benefits （i.e. reduce the unit cost of goods and fabrication process etc.） to fabrication of metallic foams. In this article, the fabrication characteristic of near net-shape metallic foams by direct foaming method was evaluated. Al and Plaster was used for base material and mould material respectively. Ca and TiH2 were added to molten Al as thickening and blowing agent for stable condition of bubbles. Thickening time was about 10 min with a stirring speed of 600 r/min. Foaming time was 30-120 s for evaluation of the optimum foaming condition. Amount of agent was selected by pre-experimental data. Porosity of near net-shape goods was measured by Archimedes method. On the other hand, it seems that increasing poring time and thickening agent make the poor porosity展开更多
The mold pressing process was applied to investigate the formability of closed-cell aluminum foam in solid–liquid–gas coexisting state.Results show that the shape formation of closed-cell aluminum foam in the solid...The mold pressing process was applied to investigate the formability of closed-cell aluminum foam in solid–liquid–gas coexisting state.Results show that the shape formation of closed-cell aluminum foam in the solid–liquid–gas coexisting state was realized through cell wall deformation and cell movement caused by primary α-Al grains that slid,rotated,deformed,and ripened within cell walls.During formation,characteristic parameters of closed-cell aluminum foam were almost unchanged.Under proper forming conditions,shaped products of closed-cell aluminum foam could be fabricated through mold pressing.展开更多
文摘Titanium(Ti)and nickel(Ni)elemental powders were blended by ball milling and the ball milled powders were employed to fabricate TiNi shape memory alloy(SMA)foams by spacer sintering.Effect of ball milling time on phase constitutes of the sintered TiNi alloy foams was studied by X-ray diffraction(XRD)analysis.Scanning electron microscopy(SEM)was used to characterize the porous structure,and compressive tests were carried out to evaluate the mechanical properties of the foams.Results indicate that porosities of the TiNi alloy foams can be controlled by using the spacer sintering method,and the porosities show a significant effect on the mechanical properties and shape memory effect(SME).
文摘Fabrication characteristics are unstable in direct foaming method. Therefore, most of near net-shape metallic foams are produced, and investigated by powder metallurgy. Direct foaming method, however, has many benefits （i.e. reduce the unit cost of goods and fabrication process etc.） to fabrication of metallic foams. In this article, the fabrication characteristic of near net-shape metallic foams by direct foaming method was evaluated. Al and Plaster was used for base material and mould material respectively. Ca and TiH2 were added to molten Al as thickening and blowing agent for stable condition of bubbles. Thickening time was about 10 min with a stirring speed of 600 r/min. Foaming time was 30-120 s for evaluation of the optimum foaming condition. Amount of agent was selected by pre-experimental data. Porosity of near net-shape goods was measured by Archimedes method. On the other hand, it seems that increasing poring time and thickening agent make the poor porosity
基金financially supported by the National Natural Science Foundations of China (No.51371104)
文摘The mold pressing process was applied to investigate the formability of closed-cell aluminum foam in solid–liquid–gas coexisting state.Results show that the shape formation of closed-cell aluminum foam in the solid–liquid–gas coexisting state was realized through cell wall deformation and cell movement caused by primary α-Al grains that slid,rotated,deformed,and ripened within cell walls.During formation,characteristic parameters of closed-cell aluminum foam were almost unchanged.Under proper forming conditions,shaped products of closed-cell aluminum foam could be fabricated through mold pressing.
