Since the first Bulk metallic glasses (BMGs) were synthesized in 1989, [1] striking progress has been made in the preparation of BMG. A great number of multicomponent metallic glass alloys with strong glass-forming ability (GFA) and high thermal stability have been discovered, including Ti, Zr, Fe, Pd, Mg, Cu, Ni, and other metallic glass alloy systems. [2][3][4] BMGs have attracted much attention due to their unique properties, for example, their superior strength and high hardness, excellent corrosion resistance and high wear resistance. Recently, many techniques have been used successfully to prepare Ti-based BMGs, but most of the research efforts and industrial interests are focused on different implementations of rapid solidification. [5] An alternative method uses solid-state amorphization processing, as in mechanical alloying (MA), to prepare amorphous powders that are suitable for further compaction and densification. Meanwhile, reinforced particles can be introduced easily into the glassy matrix. As previous investigations have demonstrated, MA has been used successfully to prepare amorphous Cu-and Zr-based composite powders. [6,7] Carbon nanotubes (CNTs) have been one of the most actively studied materials in contemporary research. These structures have good chemical and physical properties potential applications in many different fields. CNTs, with their superb electronic, mechanical, and structural characteristics, are strong candidate components for new functional devices, such as field emission displays, nanoscale transistors supercapacitors, [6][7][8] secondary batteries, and various composites. [8][9][10] Even though BMGs and CNTs have many excellent properties, a literature survey indicated that no report exists on the formation of a Ti-based BMG composite powder containing CNTs using the MA process. In this work, amorphous Ti 50 Cu 28 Ni 15 Sn 7 powders with and without CNT additions will be prepared using MA. Subsequent consolidation of asmilled powders will be performed and the mechanical property of compacts will be evaluated by a Vickers microhardness and compressive tests.
ExperimentalA mixture of elemental metallic powders with a nominal composition of Ti 50 Cu 28 Ni 15 Sn 7 (in at. %) was mechanically alloyed with or without the addition of CNT powders. The milling was performed in a SPEX 8016 shaker ball mill under an Ar-filled atmosphere. The overall mechanical alloying process lasted 8 hrs and was interrupted every 15 min for the first hour and every 30 min thereafter. Each interruption was followed by an equal length of time (30 min) to cool down the vials, and then a suitable amount of the as-milled powders was extracted, to examine the progress of amorphization reaction. Specific details of the mechanical alloying process are described elsewhere. [6] The as-milled composite powders were consolidated in a vacuum hot pressing machine to prepare bulk samples with a 10 mm diameter and 2 mm thickness. The structures of the as-milled and bulk samples were analyzed using an X-ray diffracto...
