Effects of in situ formation of TiB₂ particles on age hardening behavior of Cu-1 wt % Ti-1 wt % TiB₂

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• 作者：Mohsen Sobhani^a ; ^{m_sobhani@iust.ac.ir} ; Alireza Mirhabibi^b ; Hossein Arabi^a ; R.M.D. Brydson^c
• 关键词：Cu&ndash ; Ti ; Age hardening ; Composite ; TiB2 ; In situ
• 刊名：Materials Science and Engineering: A
• 出版年：2013
• 出版时间：10 August, 2013
• 年：2013
• 卷：577
• 期：Complete
• 页码：16-22
• 全文大小：2957 K

文摘

Age hardenable Cu-1 wt % Ti-1 wt % TiB₂ composite was produced by adding boron powder to Cu-Ti melt. TiB₂ nano-particles were formed via in situ reaction between titanium and boron in the melt. This composite was aged in a temperature range of 300-550 ¡ãC for a period of 1-25 h. Then, the age hardening behavior of the composite was compared with that of the binary Cu-2 wt % Ti alloy. The microstructure of the composite was examined with a high-resolution transmission electron microscope (HRTEM). The results of this study showed that TiB₂ particles can act as a heterogeneous nucleation site for ¦Â¡ä(Cu₄Ti) precipitates. Substantial increase in tensile and yield stress of composite (i.e. 63 % and 186 % respectively) occurred relative to the solution state, after ageing at 450 ¡ãC for 10 h. The maximum strengthening of the composite was associated with precipitation of metastable Cu₄Ti near the ultra hard TiB₂ particles within the matrix. However, the results of this research show that the mechanical properties of aged composites are in good agreement with those of binary Cu-2 wt % Ti alloy; the maximum values of the hardness and electrical conductivity of the composite (i.e. 258 HV, 28 % IACS) and the binary Cu-2 wt % Ti alloy (i.e. 264 HV, 17 % IACS) were obtained when solution treated samples were aged at 450 ¡ãC for 10 h and 15 h, respectively.