Fabrication of 93W-Ni-Fe alloy large-diameter rods by powder extrusion molding

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• 作者：Wensheng Liu ; Qingshan Cai ; Yunzhu Ma ; Qianfang Huang ; Jiajia Zhang
• 关键词：Powder extrusion molding ; Tungsten heavy alloy ; Binder ; Solvent-thermal debinding ; Extruded rod
• 刊名：International Journal of Refractory Metals and Hard Materials
• 出版年：January, 2014
• 年：2014
• 卷：42
• 期：Complete
• 页码：233-239
• 全文大小：1802 K

文摘

A powder extrusion molding (PEM) process has been used for the manufacturing of tungsten heavy alloy rods with large length to diameter ratio. An improved wax-based multi-component binder was developed for PEM of 93W-Ni-Fe alloy. The miscibility of its components and the characteristics of the binder were evaluated and good thermal-physical properties were obtained. Also, the feedstock rheological properties, extrusion molding and debinding process were studied. The feedstock exhibited a pseudo-plastic flow behavior. The large length to diameter ratio rods, with diameters up to 36 mm were extruded at 65 掳C by optimizing the extrusion process. A two-step debinding process was employed to remove the binder in the extruded rods. Solvent debinding was carried out in n-heptane at 45 掳C to extract the soluble components. A process of repeated short time immersion and drying of the extruded rods (called short-period solvent debinding) was developed and using this novel technique the binder removed was raised from 45% to 60%. SEM analyses indicated that a large volume of pores was formed in debound rods, but had not created interpenetrating pore channels yet. The rest of the binder could be thermally extracted at a high heating rate without defects.