Effects of Internal Oxidation Methods on Microstructures and Properties of Al2O3 Dispersion-Strengthened Copper Alloys
With Cu–Al alloy powder as raw material and Cu2O powder as oxidant, two internal oxidation methods, namely step-by-step internal oxidation-reduction method (referred to as the step-by-step method) and integrated internal oxidation-reduction method (referred to as the integrated method), were respectively adopted to achieve the oxidation of Al. Then hot extrusion without canning was applied to prepare Al2O3 dispersion-strengthened copper alloys. The effects of the two internal oxidation methods on microstructures and properties of the alloys were compared. The results show that both the step-by-step method and the integrated method can achieve the complete oxidation of Al. However, the excessive oxidant can not be reduced thoroughly in the integrated method. The residual oxidant increases oxidation of the sintered body during hot extrusion and the formed copper oxides distribute in the grains as well as at the grain boundaries. While in the step-by-step alloy, the copper oxides mainly distribute at the grain boundaries. The step-by-step method improves electrical conductivity and ductility, but lowers hardness and strength. The integrated alloy has worse ductility and lower electrical conductivity, but strength and hardness are higher. The step-by-step alloy has better comprehensive properties, and its electrical conductivity, hardness, tensile strength, yield strength and elongation is 89% IACS, HRB 69–72, 425 MPa, 394 MPa and 27.2%, respectively.
KeywordsAl2O3 dispersion-strengthened copper alloys Internal oxidation Hot extrusion Microstructure Physical properties
This work was supported by Guangdong Provincial Industrial High-tech Project (No. 2015A010105020), Guangzhou Sci-tech Project (No. 201707010145), Zhongshan-Guangdong Academy of Sciences technology transfer special foundation (2016G1FC0007), Guangdong Academy of Sciences Implements Innovation-driven Development Capacity Building Project (No. 2017 GDASCX-0117), Guangdong Provincial Innovation Ability Construction Project (No. 2016B070701024) and Guangzhou Innovation Platform Construction and Sharing Project (No. 201509010003).
- 1.R.F. Need, D.J. Alexander, R.D. Field, V. Livescu, P. Papin, C.A. Swenson and D.B. Mutnick, The effects of equal channel angular extrusion on the mechanical and electrical properties of alumina dispersion-strengthened copper alloys, Mater. Sci. Eng. A 565 (2013) 450–458.Google Scholar
- 2.V. Rajkovic, D. Bozic, A. Devecerski and M.T. Jovanovic, Characteristic of copper matrix simultaneously reinforced with nano- and micro-sized Al2O3 particles, Mater. Charact. 67 (2012) 129–137.Google Scholar
- 3.S.J. Hwang and J. Lee, Mechanochemical synthesis of Cu-Al2O3 nanocomposites, Mater. Sci. Eng. A 405 (2005) 140–146.Google Scholar
- 4.J. Lee, Y.C. Kim, S. Lee, J.K. Nack, S. Ahn and N.J. Kim, Correlation of the microstructure and mechanical properties of oxide-dispersion-strengthened coppers fabricated by internal oxidation, Metall. Mater. Trans. A 35 (2004) 493–502.Google Scholar
- 5.K. Dash, B.C. Ray and D. Chaira, Synthesis and characterization of copper-alumina metal matrix composite by conventional and spark plasma sintering, J. Alloy Compd. 516 (2014) 78–84.Google Scholar
- 6.Z.Q. Yan, F. Chen and Y.X. Cai, Al2O3 dispersion strengthened copper alloy prepared by high-velocity compaction, Chin. J. Nonferrous Met. 25 (2015) 747–753.Google Scholar
- 7.Z.Q. Yan, F. Chen, F.X. Ye, D.P. Zhang and Y.X. Cai, Microstructures and properties of Al2O3 dispersion-strengthened copper alloys prepared through different methods, Int. J. Miner. Metall. Mater. 23 (2016) 1437–1443.Google Scholar
- 8.M.X. Guo, M.P. Wang, K. Shen, L.F. Cao, R.S. Lei and S.M. Li, Effect of cold rolling on properties and microstructures of dispersion strengthened copper alloys, Trans. Nonferrous Met. Soc. China 18 (2008) 333–339.Google Scholar
- 9.F. Chen, Z.Q. Yan and Y.X. Cai, Properties of Al2O3 dispersion strengthened copper alloy prepared by internal oxidation and high-velocity compaction, J. Funct. Mater. 46 (2018) 8133–8137.Google Scholar
- 10.D. Feng, C.X. Shi and Z.G. Liu, Introduction to materials science, Chemical Industry Press, Beijing, 2002.Google Scholar
- 11.T.S. Srivatsan, N. Narendra and J.D. Troxell, Tensile deformation and fracture behavior of an oxide dispersion strengthened copper alloy, Mater. Des. 21(2000) 191–198.Google Scholar
- 12.A. Hajri, A. Melendez, R. Woods and T.S. rivatsan, Influence of heat treatment on tensile response of an oxide dispersion strengthened copper, J. Alloy. Compd. 290 (1999) 290–297.Google Scholar