| Directional solidified Cu-Cr in-situ composites have high strength, high electricity but without such problems of interfacial contamination and low stability as in the conventional man-made synthetic composites due to self-driven engender in the process of directional solidification, so this composites are expected to be used as contact cable, which is made for trunk line electrification. With the background of use in contact cable, this thesis introduces Cu-Cr alloys as studied subject, and from the two ways of solidified process and solidification mechanics, the structure configuration and the behave of separated-out strengthened elements are systematically study under the process of directional solidification. The main subjects and conclusions are as follows:1. A kind of directional solidification equipment of high temperature gradient and double-zone heating is self-made. The advanced double-zone heating technology is used in the directional solidification furnace, which stabilizes components and decreases the burnout of alloys. For the purpose of high temperature gradient, liquid metal cooling with circulatory water cooling is used directly to cool the sample, and at the same time, radiation baffle with appropriate size and shape is needed. Pulling velocity can be continuously adjusted within very big limits at(0. 2-850μm/s) , and during the process of pulling, the run of system is not only balanced, reliable, but no noise pollution after long time and without the phenomena of the crawling and worming under low pulling velocity. Another important characteristic of the equipment is with the function of liquid quenching.2. The growth morphology of Cu-Cr eutectic are studied. During the process of eutectic growth, (α+β) growth is clinging to a phase. Because Cu-Cr eutectic have very good coupling relation, the configuration of eutectic holds crystallography structure, and the influence of the direction of heat flow is not distinct.3. For the component of sub-eutectic, the Cu-Cr alloys are difficult to form complete eutectic tissue on the condition of non-equilibriumsolidification. The general microstructure is of cellular primary a(Cu) and circumference-distributed eutectic (a+p) where the former mainly acts as the conductor and the latter as the reinforce, together to be fibrous eutectic reinforced in-situ composites.4. Under the directional solidification, either sub- or hyper-eutectic alloys, with the increase of growth rate, the lst dendritic arm spacing decreases and 2st dendritic arm spacing is restrained to some extent.5. Under the experimental conditions, the tensile strength of directional solidification Cu-Cr alloy is markedly higher than the casting Cu-Cr alloy. And the analysis of rupture part on SEM shows the gliding series of directional solidification Cu-Cr alloy is more than the casting Cu-Cr alloy.6. Through analysis and discuss of the precipitation mechanism of Cr phase, it can be deduced that primary β(Cr) phase exhibits petal shape or triangular due to solute and heat flow in local fluid. This shows, on the course of growth, the directional ability of the primary β(Cr) phase is not manifest, and must influence the morphology and distribution of the a phase and eutectic, gravely breach the continuity of the base. So, it is adverse to make highly purity β(Cr) phase.
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