Fe microalloying during the in-situ synthesis of homogeneous CuCrFe alloys by aluminothermic self-propagating

Abstract

Microalloying is an effective approach to improve the performance of CuCr alloys. This paper presents a new idea for the preparation of CuCrFe alloys by self-propagation reduction in-situ microalloying. It is found that the addition of Fe alloying components reduces the Gm and ΔGm of the CuCr melt, which inhibits the occurrence of the liquid phase decomposition process. When the Fe content of CuCrFe alloy is 1.5%, compared with the Cr-rich phase of CuCr alloy, the second phase undergoes significant refinement, the average particle size refined from 21.7 μm to 19.3 μm and the standard deviation reduced from 10.59 to 8.73, and the addition of Fe is beneficial to the spheroidization and refinement of the Cr-rich phase. Fe is mainly combined with Cr, and CuCrFe alloy still exists in the form of two phases. After solution + aging treatment, the average particle size of the second phase in CuCr alloy decreases from 21.8 μm to 17.9 μm, and that in CuCrFe alloy decreases from 19.6 μm to 18.6 μm. The conductivity of CuCrFe alloy increases from 10.5 MS m−1 to 15.9 MS m−1, and the hardness increases from 95.0 HB to 117.0 HB. After heat treatment, the nano-spherical are present in the Cr-rich phase of the CuCrFe alloy, while Fe is completely solid-soluble in the Cr-rich phase; the Cu-rich matrix shows a diffuse distribution of fine second phases, which play a role in strengthening the second phase in the matrix.

Keywords

• CuCr alloy
• Fe microalloying
• Self-propagation reduction