Phase transformation and thermal stability of mechanically alloyed W–Ni–Fe composite materials

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 379; no. 1; pp. 148 - 153
• Main Authors: Zhang, Zhong-Wu, Zhou, Jing-En, Xi, Sheng-Qi, Ran, Guang, Li, Peng-Liang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2004; Elsevier
• Subjects: Applied sciences; Exact sciences and technology; Mechanical alloying; Metal powders; Metals. Metallurgy; Microstructure; Powder metallurgy. Composite materials; Production techniques; Solubility; Thermal stability; W–Ni–Fe; W–Ni–Fe; Microstructure; Mechanical alloying; Thermal stability; Solubility; Grain size; Differential scanning calorimetry; Volume fraction; Metal matrix composite; Tungsten base alloys; Phase analysis; X ray diffraction; Composite material; Phase transformation; Sintering; W-Ni-Fe; Chemical composition; Melting point
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2004.02.039

The tungsten heavy alloys with the composition of 93W–4.9Ni–2.1Fe in weight percent from the elemental powders of W, Ni and Fe were mechanically alloyed (MA-ed). Nano-crystalline supersaturated solid solutions with grain size of 11 nm, and amorphous phase were achieved during MA. By using a combination of differential scanning calorimetry (DSC), X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) analysis, phase transformation and thermal stability of mechanically alloyed 93W–4.9Ni–2.1Fe alloys were investigated. The results show that the melting point of 93W–4.9Ni–2.1Fe alloy milled for 60 h decreases approximately by 220 °C compared with the unmilled powderd mixture. When sintered at 1150 °C for 30 min, tungsten heavy alloys using mechanically alloyed powders show homogeneous microstructure and ultra-fine tungsten particles of approximately 2 μm with high density above 95%. The matrix of tungsten heavy alloys, sintered at 1280 °C for 30 min using MA-ed powders, shows high W solubility about 63.72 wt.% with a large amount of volume fraction of about 0.5 of matrix.