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RECENTLY, remarkable advancement in amorphous alloys has been made by the development of amorphous alloys having substantially high amorphous forming ability.[1–6] Among them, Zr-base amorphous alloys show excellent amorphous forming ability (critical cooling rate about 1 C/s, maximum sample diameter over 60 mm), hardness, stiffness, strength, and corrosion resistance.[1,3] However, they have poor ductility and toughness because brittle fracture readily occurs due to the formation of localized shear bands under tensile or compressive loading,[7–10] thereby limiting wide applications to high-performance structural components such as electronic parts, sports goods, and those of defense industry. If the process of amorphous alloy matrix composites, in which secondary phases or reinforcements having sufficient ductility and fracture toughness are homogeneously dispersed in an amorphous alloy matrix, can be newly developed, the aforementioned problems of amorphous alloys can be solved while taking full advantage of amorphous alloys. General processes of amorphous matrix composites

KYUHONG LEE, is Senior Researcher, Materials and Processes Engineering, Samsung Techwin, Changwon, 641-717, Korea. SUNGHAK LEE, Professor, Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang, 790-784, Korea, is also with the Materials Science and Engineering Department, Pohang University of Science and Technology. Contact e-mail: shlee@postech. ac.kr SANG-BOK LEE and SANG-KWAN LEE, Senior Researchers, are with Composite Materials Laboratory, Korea Institute of Materials Science, Changwon, 641-010, Korea. Manuscript submitted May 7, 2008. Article published online February 14, 2009 828—VOLUME 40A, APRIL 2009

include partial crystallization of amorphous alloys to disperse nanocrystallines,[11–13] generation of dendritic crystalline phases from the amorphous melt,[14] addition of crystalline particles to the amorphous melt,[15,16] and casting of both reinforcing fibers and amorphous alloys.[17–19] When amorphous matrix composites reinforced with continuous metallic fibers are processed by casting it is important to control reactions of the amorphous melt with fibers, since most metallic fibers except refractory fibers have high reactivity with the amorphous melt. Thus, in order to effectively process casting composites it is necessary to use metallic fibers having high thermal stability as reinforcements and to introduce new concept process technologies, one of which is a liquid pressing process[20] using low pressure near to the theoretically required minimum loading pressure. This process might be considered a reliable process of composites because the crystallization of the amorphous matrix can be prevented or minimized by rapid cooling of the amorphous melt. In this study tantalum continuous fibers, which have excellent strength and thermal stability, were used for reinforcements. An amorphous matrix composite whose matrix was a Zr-based amorphous alloy was processed by liquid pressing. Chemical reactions bet