Effects of Sintering Conditions on the Mechanical Properties of Alumina Particle Dispersed Magnesium SPS Compacts

Abstract:

To enhance the mechanical properties of Mg alloys, 0-30vol% Al₂O₃/Mg powders were formed by ball milling powder mixtures of pure Mg and Al₂O₃ particles, and then Spark plasma sintering (SPS) compacts (Al₂O₃/Mg discs) were made by the Al₂O₃/Mg powders. The effect of the cooling conditions in the SPS process on the mechanical properties of the Al₂O₃/Mg discs was investigated. From the results of SEM, XRD and TEM-EDS, the microstructures of the Al₂O₃/Mg discs were identified to consist of α-Mg solid solution, Al₂O₃ particles, refined MgO particles and refined needle-like Mg₁₇Al₁₂ ( more than 20vol% Al₂O₃ content). The mechanical properties of the discs were able to control by the regulation of the cooling conditions (cooling rate (v_c) and applied pressure in the cooling (p_c)) in SPS process, and as a result, the SPS discs possessing the mechanical properties beyond HP compacts were obtained under the cooling conditions of “v_c = 0.83K/s and p_c = 20MPa”. Main factor that the cooling conditions in SPS process effect on the mechanical properties of the Al₂O₃/Mg discs are considered to be the compresive residual stress generated in the α - Mg solid solution by the thermal stress associated with deference of the coefficients of thermal expansion between the α - Mg and ceramics particles (Al₂O₃ and MgO) in the discs.

• Periodical: Materials Science Forum (Volumes 783-786)
• Pages: 2433-2438
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.783-786.2433
• Online since: May 2014
• Authors: Shigehiro Kawamori*, Hiroshi Fujiwara, Yukio Kasuga
• Keywords: Alumina Particle Dispersed Magnesium Powder, Bending Strength, Cooling Conditions, Hardness, Spark Plasma Sintering (SPS), Tensile Strength

References

[1] S. Kawamori, K. Kuroda, Y. Kasuga, M. Yokouchi, H. Fujiwara and K. Ameyama: Mater. Trans., 51(2010), p.1893.

DOI: 10.2320/matertrans.m2010060

[2] S. Kawamori, K. Kuroda, H. Fujiwara and K. Ameyama: Mater. Sci. Forum, 706-709(2012), p.1915.

[3] S. Kawamori, H. Fujiwara, K. Kuroda and Y. Kasuga: steel research international, special ed., (2012), p.823.

[4] M. M. Avedesian and H. Baker: ASM Speciality Handbook, Magnesium and Magnesium alloys, (ASM international, 1999), p.10.

[5] Y. Nishikado: Magnesium Manual 1996, (The Japan Magnesium Association, 1996), p.9.

[6] J. H. Adams, et al.: ASM HAND BOOK Volume 2, (ASM international, 1990), p.1099.

[7] M. Bauccio: ASM Metal References Book 3rd ed., (ASM international, 1993), p.145.

[8] K. Niwa, et al.: Handbook of Ceramics 2nd ed., (Gihodo shuppan Co. Ltd., 2002), p.96.

[9] V. Goryany and P .J. Mauk: J. Mining and Metallurgy, 43B (2007), p.85.