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Formation of amorphous NiTa alloy powders by mechanical alloying
| Content Provider | Semantic Scholar |
|---|---|
| Author | Chen, T.-R. |
| Abstract | The mechanical alloying process was developed during the early 1970s for the production of oxide dispersion strengthened superalloy powders [1]. It is performed in a high-energy ball mill, most frequently in a shaker mill (research scale) or an attritor grinding mill (industrial scale). The process consists of repeated mechanical mixing, cold welding, fracturing and rewelding of ultrafine alloy powder [1]. Mechanical alloying can produce homogenous alloys from elements that cannot be alloyed by diffusion, sintering or melting. Using this technique, it is possible to develop "synthetic" alloys with unique properties. Recently, Koch et al. [2] reported that amorphous Ni60Nb40 powders can be produced by mechanical alloying of crystalline pure nickel and niobium powders. Subsequently many amorphous binary metals alloys have been formed by mechanical alloying of the elemental powders [3-6]. All of these systems have large negative enthalpies of mixing and it is believed that the driving force for amorphization is essentially the same as in solid state interdiffusion reactions [7]. However, a survey of the available literature indicates that little work has been carried out on the amorphization of Ni-Ta binary alloy by mechanical alloying of elemental Ni and Ta powders. Therefore, the purpose of the present research was to study the preparation of amorphous Ni-Ta powders by mechanical alloying of elemental Ni and Ta powders using a planetary ball mill. Elemental powders of Ni (99.9%, <325 mesh) and Ta (99.98%, <325 mesh) were accurately weighted to give the desired compositions: NixTal00_ x (x = 20, 30, 40, 50, 60, 70, 80). The preweighed powder mixtures were canned into an SKH 9 high speed steel vial together with CR steel balls (10 mm in diameter) under argon atmosphere within a glove box. The ball-to-powder weight ratio was 5:1. A Fritsch P7 planetary ball mill was employed for the mechanical alloying process. The mill was installed inside a glove box in order to control the milling atmosphere. An oxygen analyser was used to detect the oxygen content of the glove box. The mechanical alloying process was started when the analyser indicated that the oxygen content was undetectable. A suitable quantity of the mechanically alloyed powders was taken out of the steel vial periodically to observe the progress of alloying by X-ray diffraction (XRD) and optical microscopy. The X-ray investigation was performed in a Rigaku D/MAX IIIA diffractometer using CuKo~ radiation with a nickel filter. The stability of the amorphous |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://page-one.springer.com/pdf/preview/10.1007/BF00273239 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
