Microstructure- and property-controllable NdAlNiCuFe alloys by varying Fe content
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We report the formation of microstructure- and property-controllable Nd60Al10Ni10Cu20-xFex (0 艋 x 艋 20) alloys by varying the content of Fe element. The microstructure of the Nd-based alloy can be changed progressively from a full glassy state into a composite state with nanocrystalline particles in the glassy matrix and, finally, into a nanostructured state, accompanied by variation in magnetic property gradually from paramagnetic to hard magnetic. The role of Fe addition in the control of microstructure and magnetic property is clarified. We expect that the results would have implication in the development of the microstructure- and property-controllable functional materials for various applications.
I. INTRODUCTION
Microstructure- and property-controllable alloys are expected to be used in a variety of technological contexts. However, the microstructural control in the metallic alloys is a longstanding problem due to the high nucleation and growth rates and instability of their supercooled liquid state. Bulk metallic glass (BMG)-forming alloys with a very stable supercooled liquid state and high thermal stability against crystallization1,2 offer a large experimentally accessible time and temperature window for developing some methods, such as controlled solidification,3,4 high annealing,5,6 and pressure,7 to control their microstructure and properties through controlling of the nucleation and growth in supercooled liquid state. The rare-earth (RE)-metal-based alloys have attracted intensive attention due to their high glass-forming ability (GFA), and anomalous magnetic properties.8–12 For Nd-based alloys, it was reported that the bulk glass rod with 12 mm diameter can be obtained by suction casting into a copper mold.7 However, the Nd-based BMGs actually are regarded as a type of clustered amorphous material. Direct evidences are that the BMGs have no obvious glass transition in their differential scanning calorimeter (DSC) traces as other BMGs have done and exhibit hard magnetic, while ribbons with the same composition are magnetically soft.9–11 In our previous work, we found that element addition is an effective way to influence the GFA, properties, and
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Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2005.0038 314
http://journals.cambridge.org
J. Mater. Res., Vol. 20, No. 2, Feb 2005 Downloaded: 14 Mar 2015
microstructure of the BMG-forming alloys.13–19 Fe content is found to have a significant effect on the magnetic properties and GFA of the Nd-based alloys.8–10 Therefore, it is possible to control the microstructure and magnetic properties of the Nd-based alloys by Fe addition. In this paper, we report the formation of full bulk glassy Nd60Al10Ni10Cu20 alloy. Based on the BMG, the microstructure and property are manipulated in the alloy by controlling additional Fe content. By varying Fe content, the microstructure of the Nd-based alloy changes progressively from full glassy state to composite state with nanocrystalline particles in the glassy matrix, and fin
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