| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1985: ¥1,100,000 (Direct Cost: ¥1,100,000)
|
|---|
| Research Abstract |
In recent years, a powder metallurgy (P/M) method combined with rapid solidification (RS) techniques have attracted considerable attention, because this process could improve elevated temperature mechanical properties and also low density-high modulus. However, aluminum tapes inherently exhibit a surface oxide layer, which affects detrimentally mechanical properties and particularly ductility of P/M products when incompletely broken up or nonuniformly distributed during consolidations and hot working.
The object of this study is to clarify the behavior of surface oxide layer during hot consolidation and extrusion of splat-quenched two kinds of alloys, one is Al-Cr-Zr alloys and the other is Al-Li-Zr containing higher concentration of Li than that in an ordinary I/M alloy.
In splat-quenching techniques, molten droplets were injected into two kinds of atomospheres, one is experimental laboratory air and the other is dry argon to change the degree of oxidation and hydration.
The microstructures of these tapes in the conditions of as-splat as well as heat treated by means of optical, transmission and scanning electron microscopy, selected area electron diffraction and X-ray.
The tapes were hot pressed in a vacuum to produce billete, and hot pressed billete were subsequently hot extruded to make wires by extrusion ratio 1 : 20 or 1 : 18.
In the hot pressed billets , oxide layers still remains on the prior tape boundary area, and after hot extrusion, the oxide layer were broken up into film fragments.
However, the ductility was concluded to be quite different between Al-Cr-Zr and Al-Li-Zr alloys.
In the case of Al-Cr-Zr alloys, the ductility was improved by the sufficient hot extrusion, but it was not the case for Al-Li-Zr where it may be necessary to avoid completely a formation of oxide surface layers.
|
