Preparation of fine-grained tungsten heavy alloys by spark plasma sintered W–7Ni–3Fe composite powders with different ball milling time
Preparation of fine-grained tungsten heavy alloys by spark plasma sintered W–7Ni–3Fe composite powders with different ball milling time
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DOI：
10.1016/j.jallcom.2013.02.014
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发表时间：
2013-06
影响因子：
6.2
通讯作者：
D. Xiang;Ding Lei;Y. Y. Li-Y.;Guangxu Chen;Yuwei Zhao
中科院分区：
文献类型：
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作者：
D. Xiang;Ding Lei;Y. Y. Li-Y.;Guangxu Chen;Yuwei Zhao
采用放电等离子烧结W-7 Ni-3Fe复合粉末，通过不同的高能球磨时间，成功制备了晶粒尺寸约为1-3μm的细晶钨基高比重合金。本文分析了高能球磨时间不仅对复合粉末，而且对钨合金的显微组织和力学性能的影响。采用扫描电子显微镜（SEM）和X射线衍射仪（XRD）分别研究了粉末和合金的微观结构和相演变规律。球磨粉末的XRD图谱中未观察到γ-（Ni，Fe，W）相。随着HEBM时间的延长，W相衍射峰越来越宽，强度不断下降。然而，即使在HEBM 40 h之后也没有形成完全非晶结构。随着球磨时间的增加，HEBM辅助SPS技术制备的WHA的相对密度逐渐降低。在1150°C保温8 min烧结的钨合金，随着HEBM时间的延长，W晶粒逐渐细化，γ-（Ni，Fe，W）粘结相含量显著增加。同时，HEBM时间超过5 h，抗弯强度继续下降，硬度略有增加。W晶粒的沿晶断裂是所有WHA的主要弯曲断裂方式。不同尺寸的微孔分布在弯曲断口上，并随着球磨时间的延长而逐渐增多。
The fine-grained tungsten heavy alloys (WHAs) with grain size of about 1–3μm were successfully prepared by spark plasma sintered W–7Ni–3Fe composite powders with different high-energy ball milling (HEBM) time. This study analyzes the effects of HEBM time not only on the composite powders but on the microstructure and mechanical properties of WHAs. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to investigate the microstructure and phase evolution rules of powders and alloys, respectively. The γ-(Ni, Fe, W) is not observed in XRD patterns of the ball milled powders. With prolonging HEBM time, the W phase diffraction peak becomes increasingly wider, and its intensity continues to decline. However, the completely amorphous structures are not formed even after HEBM 40h. The relative density of the WHAs prepared by HEBM assisted SPS technique decreases gradually with increasing the ball milling time. For the WHAs sintered in 1150°C for 8min, the W grains grow finer and the content of the γ-(Ni, Fe, W) binding phase greatly increases with prolonging the HEBM time. Meanwhile, over 5h of HEBM time, the bending strength continuously decreases and the hardness slightly increases. The intergranular fracture of the W grains is the main bending fracture mode in all the WHAs. The microporous of different sizes are distributed on the bending fracture and progressively increased with prolonging the ball milling time.