Synthesis and Mechanical Properties of New Cu-Zr-based Glassy Alloys with high Glass-Forming Ability
✍ Scribed by W. Zhang; Q. Zhang; A. Inoue
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 464 KB
- Volume
- 10
- Category
- Article
- ISSN
- 1438-1656
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✦ Synopsis
Since the synthesis of bulk glassy alloys in multi-component Ln- [1] (Ln: lanthanide metal) and Mg- [2] based alloys by the copper mold casting method in 1989, much effort has been devoted to develop new bulk glassy alloys exhibiting high glass-forming ability (GFA) and useful engineering properties. As a result, bulk glassy alloy systems have been extended to Zr-, [3,4] Fe-, [5] Cu-Ti-, [6] Pd-, [7,8] Ti-, [9] Co-, [10] Ni-, [11][12][13] Hf-, [14] Cu-, [15][16][17] Ca-, [18] Pt- [19] and Au- [20] based alloys. These bulk glassy alloys exhibit unique properties such as high strength, large elastic strain limit, high hardness, good soft magnetic properties, and viscous flow workability in the supercooled liquid region and excellent corrosion resistance. However, to date, large-sized bulk glassy alloys with critical diameters larger than 1 cm were formed in only about 20 types; and with diameters larger than 2 cm are available only in Zr-, [21][22][23] Pd-, [7,8] Pt-, [19] Mg- [24] and Ln- [25][26][27] based alloy systems.
Recently, it has been reported that Cu-Zr-based Cu-Zr-Ag-Al glassy alloys exhibit high reduced glass transition temperature (T rg = T g /T l , [28] T g : glass transition temperature) and c values (c= T x / (T g + T l ), [29] T x : crystallization temperature) as well as a large supercooled liquid region (D T x = T x -T g ), [30] enabling the formation of bulk glassy alloy rods with diameters of 7-15 mm by copper mold casting. [31][32][33] However, the reason for the quaternary alloys with high GFA remains unclear. In addition, little is known about the optimization of the composition in order to obtain the best glass formation in this system. This paper aims to examine the thermal stability, melting behavior, solidified structure and GFA of Cu-Zr-Ag-Al glassy alloys, and to determine the best GFA composition in this alloy system. The effects of additional Pd on the thermal stability and GFA of Cu-Zr-Ag-Al glassy alloys were also examined. In addition, the mechanical properties of these bulk glassy alloys with high GFA were investigated.