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The hydrogen ductilisation process (HyDP) for NdFeB alloys

Brooks, Oliver Peter (2018)
Ph.D. thesis, University of Birmingham.

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Abstract

The work in this thesis aims to investigate the ductility of s-HD (solid hydrogenation disproportionation) processed book mould cast NdFeB material in order to develop a novel processing route for producing fully dense magnetic material with a high energy product. A major drawback of NdFeB–based alloys is that they are extremely brittle. Therefore, to produce a fully dense magnet these alloys must be broken down into a powder and hot pressed or sintered followed by cutting and grinding to the desired shape and precise dimensions. This process is time consuming, energy intensive and produces a significant amount of waste which is not readily recyclable. This thesis reports a potentially new application of hydrogen as a promising high temperature processing tool in which the normally brittle Nd$$_2$$Fe$$_1$$$$_4$$B based intermetallic absorbs and reacts with hydrogen, converting it into a ductile, disproportionated condition, which can be subsequently compressed at room temperature. It can then be restored to its original state by removal of the hydrogen under partial vacuum at elevated temperatures. By maintaining a solid form throughout, almost zero waste material is produced and the deformed material exhibits a high coercivity and a useful degree of anisotropy.

Type of Work: Ph.D. thesis. Walton, Allan Colleges (2008 onwards) > College of Engineering & Physical Sciences Department of Metallurgy and Materials Embargo until: 31/07/2022 TN Mining engineering. MetallurgyTP Chemical technology University of Birmingham 8433
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