Materials (Mar 2024)

Effect of Al/Ni Ratio on the Microstructure and Properties of Nickel–Aluminum Bronze Alloys

  • Yinxun Tan,
  • Haofeng Xie,
  • Xue Feng,
  • Shuhui Huang,
  • Wenjing Zhang,
  • Lijun Peng,
  • Wanyu Wang,
  • Yizhi Zhao

DOI
https://doi.org/10.3390/ma17061330
Journal volume & issue
Vol. 17, no. 6
p. 1330

Abstract

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To study the effect of aluminum and nickel elements on the microstructures and properties of the nickel–aluminum bronze (NAB) alloy, four kinds of alloys with different compositions, ZCuAl7–7–4–2, ZCuAl8-6-4-2, ZCuAl9-5-4-2, and ZCuAl10-4-4-2, are prepared by vacuum-melting technology. The effects of different Al/Ni ratios on the microstructures of NAB are investigated using a metalloscope, scanning electron microscopy, transmission electron microscopy, and XPS analysis. The mechanical property is evaluated with microhardness testing and tensile mechanical testing. The corrosion resistance is evaluated using mass-loss testing, electrochemical testing, and corrosion-product characterization. The results show that with the increase of the Al/Ni ratio, the content of precipitated phases increases, while β′ and hard κ, which have a different morphology, appear. As the Al/Ni ratio rises from 1 to 2.5, the hardness increases from 104 HV to 202 HV, and the tensile strength increases by 394 MPa from 356 MPa to 751 MPa, but the elongation decreases substantially from 50.50% to 11.00%. The best corrosion resistance is shown on ZCuAl7-7-4-2, with a corrosion rate of 0.00267 mm/a after 30 d of static immersion corrosion in 3.5 wt.% NaCl solution. Through electrochemical testing and corrosion-product characterization, it is found that ZCuAl7-7-4-2 has the largest polarization resistance Rp, and the selective corrosion of the surface is mild.

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