Microstructure evolution of Zr 2 Al 3 C 4 in Cu matrix
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J.Y. Wang and Y.C. Zhoua) Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China (Received 9 July 2010; accepted 21 September 2010)
Interfacial reaction and microstructure evolution in a Zr2Al3C4 reinforced Cu composite were studied by x-ray diffraction, Raman spectroscopy, and transmission electron microscopy. Decomposition of Zr2Al3C4 was triggered by the deintercalation of Al atoms. In the initial reaction stage, depletion of Al occurred locally. ZrC and Cu platelets as well as thin twinned ZrC slices were observed inside the Zr2Al3C4 grains. In the later reaction stage, all Al atoms depleted from Zr2Al3C4 and were dissolute into the Cu matrix. The final reaction products were a Cu–Al solid solution, ZrC0.5, and highly disordered graphite, which resulted in large volume shrinkage. These experimental results provided a baseline for controlling interfacial reaction and microstructure development in Cu/Zr2Al3C4-based particle-reinforced Cu composites for optimized mechanical and electrical properties.
I. INTRODUCTION
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2010.52
possesses higher modulus, strength, and hardness than those of Ti3AlC2.15–18 In the previous work, we synthesized a highly conductive and strengthened Cu matrix composite by adding Zr2Al3C4 particles.19 The electrical conductivity of the Cu/Zr2Al3C4 composite is comparable to that of Cu/graphite, which has been extensively used in sliding electrical contact applications, while the Cu/Zr2Al3C4 composite possesses superior mechanical properties. Although bulk Zr2Al3C4 ceramic has higher strength and hardness than those of Ti3AlC2, the tensile strength of Cu/Zr2Al3C4 composite is much lower than that of Cu/Ti3AlC2 composite. In the Cu/Ti3AlC2 composite,20 a high-strength interfacial layer composed of Cu–Al solid solution and TiCx forms, which helps to transfer the load from the matrix to the reinforcement. In the newly developed Cu/Zr2Al3C4 composite, Zr2Al3C4 particles are mechanically gripped by Cu matrix,19 which does not favor the load transfer and results in the limited strengthening effects. Because the microstructures and properties of materials are generally related, characterizing and understanding the microstructure evolution are essential for optimizing the processing parameters and performance of Cu/Zr2Al3C4 composite. In addition, braze is a common jointing material between ultrahigh temperature ceramic and metal.21–24 Understanding the reaction between Zr2Al3C4 and Cu matrix will also help to evaluate the joining between Zr2Al3C4 and Cu, enabling applications of Zr2Al3C4 as high-temperature coatings. In this work, we investigate the structure stability of Zr2Al3C4 in a Cu matrix by annealing the as-synthesized Cu/30 vol%Zr2Al3C4 samples in the temperature range
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Ó Materials Research Society 2011
Copper (Cu) has widespread applications, such as heat exchangers, make-and-break electric switches, and sliding contact m
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