A low Sn content Cu-Ni-Sn alloy with high strength and good ductility

Significance 

Copper-Nickel-Tin alloy materials have important potential applications in the areas of aerospace engineering and oil and gas exploration. This can be attributed to their exceptional mechanical properties and excellent corrosion resistance. Unfortunately, macro-segregation of tin during the solidification process has remained a great challenge in developing high-performance Cu-Ni-Sn alloys,especially with high Sn content. To this end, effective techniques for preventing macro-segregation of tin is highly desirable.

Previously development of Cu-15Ni-8Sn alloys has proved unsuitable for preventing macro-segregation of tin. Alternatively, the strength property of low Sn content Cu-Ni-Sn alloys have been enhanced through a micro-alloying process which inhibits the phase growth along the grain boundary. Despite the remarkable improvements, the development of more efficient methods for enhancing the mechanical properties of low tin content Cu-Ni-Sn alloys has continued to attract significant attention of researchers. For instance, the addition of aluminum elements has shown significant potential for improving the strength of these alloy materials. Generally, aluminum exhibits solid solution hardening effects which are the main factor for enhancing the strength properties for Cu-Ni-Sn alloys.

Researchers at South China University of Technology: Baomin Luo, Daoxi Li, Chao Zhao (PhD student), Professor Zhi Wang, Dr. Zongqiang Luo and Professor Weiwen Zhang from the Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials accessed the feasibility of enhancing the mechanical properties of low Sn content Cu-Ni-Sn alloys through addition of Al and Si. Also, they investigated the effects of Al and Si on the mechanical properties of the produced Cu-Ni-Sn alloys. Their research work is currently published in the research journal, Materials Science and Engineering A.

In brief, the authors looked at the macro-segregation of Sn, its effects and how to effectively prevent it. Secondly, they developed a new low Sn-containing Cu-Ni-Sn alloys through casting and hot extrusion methods. Next, Al and Si contents were added to the resulting alloy and their strengthening effects examined thoroughly. Finally, they generally investigated the overall effects of the added Al and Si on the mechanical properties of the alloys.

The authors observed that the produced alloy material exhibited remarkable ductility and high strength. For instance, The ultimatedtensilestrength and elongation were recorded as 861Mp and 18% respectively. In addition, the addition of Si to Cu-Ni-Sn-Al alloy significantly improved the mechanical properties through desired changes in the alloy microstructures.

In summary, the South China University of Technology researchers successfully synthesis a low Sn bearing Cu-9Ni-2.5Sn-1.5Al-0.5Si alloy material with exemplary mechanical properties. The enhanced strength was generally attributed to several factors including precipitation strengthening, grain refinement, twin boundary strengthening and texture strengthening. Altogether, the study will advance the development of high-performance Cu-Ni-Sn alloys with the desired properties for numerous applications.

About the author

Weiwen Zhang, is a professor at University of Science of Technology in China. He obtained his BSc, MSc and PhD in 1991, 1995 and 1998 respectively. His research covers a wide range of materials science and engineering, with special interest in non-ferror materials, such as copper alloys and aluminum alloys. He is an author of over 200 journal publications and 30 patents.

.

Reference

Luo, B., Li, D., Zhao, C., Wang, Z., Luo, Z., & Zhang, W. (2019). A low Sn content Cu-Ni-Sn alloy with high strength and good ductility. Materials Science and Engineering: A, 746, 154-161.

Go To Materials Science and Engineering: A

Check Also

New understanding of the underlying deformation mechanisms governing the mechanical behavior of cast iron - Advances in Engineering

New understanding of the underlying deformation mechanisms governing the mechanical behavior of cast iron