Influence of B and Nb Additions and Heat Treatments on the Mechanical Properties of Cu-Ni-Co-Cr-Si Alloy for High Pressure Die Casting Applications

During the high pressure die casting process (HPDC), it is necessary to develop new designs and alloys for the copper plungers. In this research, two alloys Cu-9Ni-1Co-1.6Cr-2Si-1.3Fe-0.25B wt.% (A1) and Cu-9Ni-1Co-1.6Cr-2Si-0.1Fe-0.2Nb wt.% (A2) under different heat treatments (HT) were studied. Optical microscopy technique was applied to reveal the regions of dendritic morphology, also lower Secondary Dendrite Arm Spacing (SDAS); and different grain orientations. The results reveal that the solidification sequence is primary Cu dendrites and secondary intermetallics; heat treatments increase the redistribution of alloying elements in the interdendritic regions. During the heat treatments, some precipitates were found in the grain boundary after aging heat treatments for both alloys, which were determined by X-ray diffraction. Hardness test HRB presented a decrease with the solution heat treatment and an increase with the aging heat treatments proposed for both alloys. Finally, the wear resistances for both alloys were compared with a commercial alloy C17530, with decreased A1 with B additions having the best result in the as-cast condition 4.07 × 10−4 mm3/Nm, while for A2 with Nb additions wear resistance increased, with the best result in the one with aging heat treatment 1.69 × 10−4 mm3/Nm while for the C17530 alloy this was 2.74 × 10−4 mm3/Nm.

[1]  Q. Lei,et al.  Microstructural evolution, phase transition, and physics properties of a high strength Cu–Ni–Si–Al alloy , 2019, Materials Characterization.

[2]  C. Dong,et al.  Minor-alloyed Cu-Ni-Si alloys with high hardness and electric conductivity designed by a cluster formula approach , 2017 .

[3]  Jiango Li,et al.  Effect of Co Addition on Microstructure and Properties of Cu–Ni–Si Alloy , 2017 .

[4]  P. Boffetta,et al.  A mortality study of beryllium workers , 2016, Cancer medicine.

[5]  Huijun Kang,et al.  Effects of Cr and Zr additions on microstructure and properties of Cu-Ni-Si alloys , 2016 .

[6]  Hou-Gaung Chen,et al.  Improvement in strength and thermal conductivity of powder metallurgy produced Cu–Ni–Si–Cr alloy by adjusting Ni/Si weight ratio and hot forging , 2015 .

[7]  Hou-Gaung Chen,et al.  Effects of heat treatment processes on the microstructures and properties of powder metallurgy produced Cu–Ni–Si–Cr alloy , 2014 .

[8]  Q. Lei,et al.  A new ultrahigh strength Cu-Ni-Si alloy , 2013 .

[9]  J. H. Lee,et al.  Effect of V addition on hardness and electrical conductivity in Cu-Ni-Si alloys , 2013, Metals and Materials International.

[10]  Raymond F. Wegman,et al.  Copper and Copper Alloys , 2013 .

[11]  V. Lenin,et al.  The United States of America , 2002, Government Statistical Agencies and the Politics of Credibility.

[12]  L. Collini Copper Alloys - Early Applications and Current Performance - Enhancing Processes , 2012 .

[13]  Sangshik Kim,et al.  Effect of Ti addition on tensile properties of Cu-Ni-Si alloys , 2011 .

[14]  A. Paxton,et al.  Boron in copper: A perfect misfit in the bulk and cohesion enhancer at a grain boundary , 2007, 0711.1629.

[15]  W. Sanderson,et al.  Lung cancer case-control study of beryllium workers. , 2001, American journal of industrial medicine.

[16]  H. Tsubakino,et al.  Precipitation sequence for simultaneous continuous and discontinuous modes in Cu–Be binary alloys , 1993 .

[17]  K. Steenland,et al.  A mortality study of workers at seven beryllium processing plants. , 1992, American journal of industrial medicine.

[18]  K. Steenland,et al.  Lung cancer incidence among patients with beryllium disease: a cohort mortality study. , 1991, Journal of the National Cancer Institute.

[19]  Joseph R. Davis Properties and selection : nonferrous alloys and special-purpose materials , 1990 .

[20]  J. L. Meijering,et al.  Calculation of the nickel-chromium-copper phase diagram from binary data , 1957 .