In-situ metal matrix composite steels: Effect of alloying and annealing on morphology, structure and mechanical properties of TiB₂ particle containing high modulus steels

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• 作者：R. Aparicio-Ferná ; ndez ; H. Springer ; ^{h.springer@mpie.de" class="auth_mail" title="E-mail the corresponding author} ; A. Szczepaniak ; H. Zhang ; D. Raabe
• 关键词：Metal-matrix-composites ; Steels ; Liquid metallurgy ; Density ; Young's modulus
• 刊名：Acta Materialia
• 出版年：2016
• 出版时间：1 April 2016
• 年：2016
• 卷：107
• 期：Complete
• 页码：38-48
• 全文大小：4378 K

文摘

We systematically study the morphology, size and dispersion of TiB₂ particles formed in-situ from Fe–Ti–B based melts, as well as their chemical composition, crystal structure and mechanical properties. The effects of 5 wt.% additions of Cr, Ni, Co, Mo, W, Mn, Al, Si, V, Ta, Nb and Zr, respectively, as well as additional annealing treatments, were investigated in order to derive guidelines for the knowledge based alloy design of steels with an increased stiffness/density ratio and sufficiently high ductility. All alloying elements were found to increase the size of the coarse primary TiB₂ particles, while Co led to the most homogeneous size distribution. The size of the eutectic TiB₂ constituents was decreased by all alloying additions except Ni, while their aspect ratio was little affected. No clear relation between chemical composition, crystal structure and mechanical properties of the particles could be observed. Annealing of the as-cast alloys slightly increased the size of the primary particles, but at the same time strongly spheroidised the eutectics. Additions of Co and Cr appear thus as the best starting point for designing novel in-situ high modulus metal matrix composite steels, while using Mn in concert with thermo-mechanical processing is most suited to adapt the matrix' microstructure and optimise the particle/matrix co-deformation processes.