• Jan, Vít
• Adam, Ondřej

Abstract

In the last years, immiscible alloys have gained significant attention, mainly due to the use of their immiscible nature for the preparation of new advanced multiphase alloys. Most of these alloys are based on the Cu-Fe system. The advantages of Cu and Fe elements are their easy availability and low price, good mechanical properties, and medium melting temperature. Currently, most bulk Cu-Fe-based immiscible alloys are produced by casting. However, this method requires several additional steps to obtain appropriate microstructure. An interesting alternative is powder metallurgy, which provides an easy way to produce immiscible alloys with very fine heterogeneous microstructure. An essential requirement is to prepare a milled powder with a sufficiently small particle size, which consists of a metastable solid solution of all elements. The small particle size allows achieving full density during sintering, in which supersaturated solid solution decomposes into a fine dual-phase microstructure. In this work, two sets of milling conditions ("soft" and "hard") for the preparation of CuFe powders were tested. They differed in the milling speed and the size of milling balls. The milled powders were analyzed after several milling times and the evolution of powder particle size, morphology, and microstructure were evaluated. Based on the results, optimal milling times were selected for both sets of milling conditions and these parameters were verified by the preparation of new CuFe milled powders. Surprisingly, different results were obtained as the resulting powder particle sizes were significantly larger.

Topics

• density
• impedance spectroscopy
• microstructure
• morphology
• phase
• grinding
• milling
• casting
• sintering
• melting temperature