Glass-Forming Ability for Mg-Cu-Nd Alloys
- PDF / 903,220 Bytes
- 6 Pages / 593.972 x 792 pts Page_size
- 74 Downloads / 223 Views
INTRODUCTION
SINCE Mg65Cu25Y10 bulk metallic glass (BMG) was synthesized by Inoue et al. in 1991,[1] many BMGs based on this alloy were developed, such as Mg-Cu-Y-Ag,[2] Mg-Cu-Y-Ag-Pd,[3] and Mg-Cu-Y-Zn[4] glass-forming alloys. Experimental results show that one or more elements addition will sometimes significantly improve the GFA of the original ternary alloys. Therefore, the finding of BMGs in the ternary alloy system is very important in order to further determine better BMG formers. Recently, much research related to the GFA of Mg-based alloys was focused on Mg-Cu-Y[5,6] and Mg-Cu-Gd[7–9] ternary alloys, and many metallic glass formers with better GFA were produced.[10,11] In fact, the Mg65Cu25Gd10 alloy was also produced based on the Mg65Cu25Y10 alloy by simply using Gd to substitute for Y in MenÕs work.[7] Although such a simple substitution process may give us many hints in finding new BMGs, it cannot give the glass former with the best GFA in the interested alloy systems. For example, Xi et al.[8] have used Gd, Pr, Nd, Tb, and Dy to substitute for Y in the Mg65Cu25Y10 formula. Among them, the GFA is not larger than 1 and 4 mm in diameter for Mg65Cu25Nd10 and Mg65Cu25Y10 alloys, respectively. In order to improve the GFA of Mg-based alloys, composition optimization and additional element addition based on K.Q. QIU, Y.L. REN, and X.G. YUAN, Professors, Q.F. LI, Doctoral Candidate, are with the School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110023, People’s Republic of China. Contact e-mail: [email protected] W.H. JIANG, Research Assistant Professor, is with the Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37990. This article is based on a presentation given in the symposium entitled ‘‘Bulk Metallic Glasses IV,’’ which occurred February 25–March 1, 2007 during the TMS Annual Meeting in Orlando, Florida under the auspices of the TMS/ASM Mechanical Behavior of Materials Committee. Article published online November 2, 2007 1882—VOLUME 39A, AUGUST 2008
the ternary alloys are necessary. XuÕs group has done excellent work recently in this area. First, they optimized the compositions of Mg-Cu-Y[5] and Mg-Cu-Gd[9] alloys, finding that BMGs with diameters of 9 and 12 mm can be fabricated for Mg58.5Cu30.5Y11 and Mg61Cu28Gd11 alloys, respectively. Furthermore, they obtained BMGs with diameters of 16 and 25 mm at and composition points of Mg54Cu28Ag7Y11 Mg54Cu26.5Ag8.5Gd11, respectively, by adding the fourth element, Ag, based on Mg-Cu-Y and Mg-Cu-Gd alloy systems, respectively.[10] However, no BMGs based on Mg-Cu-Nd were systemically searched up to now according to our knowledge. For ternary Mg-Cu-RE (RE = rare earth elements) alloys, on one hand, Nd is challengeable in cost compared with other rare earth metals, such as the Y and Gd that are frequently used in the previous research. On the other hand, Nd has the largest PoissonÕs ratio (0.28[11]) among the most commonly used rare earth metals (such as Y and Gd, for which PoissonÕs rati
Data Loading...
