scholarly journals Surface Crystallization in Mg-Based Bulk Metallic Glass during Copper Mold Casting

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Xin Wang
Keyword(s):  
Metallic Glass ◽  
Cooling Rate ◽  
Bulk Metallic Glass ◽  
Casting Process ◽  
Copper Mold ◽  
Copper Mold Casting ◽  
Internal Part ◽  
Mold Casting ◽  
Injection Casting ◽  
Cast Surface

The localized crystallization of Mg54Cu28Ag7Y11bulk metallic glass (BMG) in the injection casting process using a copper mold was investigated. It has been found that several crystalline phases were formed close to the as-cast surface but did not exist in the internal part of the BMG plate. It is abnormal that the as-cast surface is partially crystallized with higher cooling rate than that of inside. Overheating of the melt and nucleation induced by the surface of copper mold play key roles in the abnormal crystallization. It is suggested that the function of copper mold to trigger heterogeneous nucleation cannot be totally ignored, although it provides the high cooling rate for the glass formation during casting.

A new Mg65Cu7.5Ni7.5Zn5Ag5Y10 bulk metallic glass with strong glass-forming ability

2003 ◽  
Vol 18 (10) ◽  
pp. 2288-2291 ◽  
Author(s):  
H. Ma ◽  
E. Ma ◽  
J. Xu
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Glass Forming Ability ◽  
Copper Mold ◽  
Glass Forming ◽  
Copper Mold Casting ◽  
Mold Casting

We report a new Mg-based bulk metallic glass-forming alloy: Mg65Cu7.5Ni7.5Zn5 Ag5Y10. The alloy exhibits a glass-forming ability significantly stronger than all previously discovered Mg-based glass formers. Fully glassy rods 9 mm in diameter can be obtained by using copper mold casting. The critical cooling rate for glass formation was estimated to be <50 Ks−1. The reduced glass-transition temperature (Trg) of the glass was determined to be 0.59.

Studies on Fe-Cr-Ni-Si-B Bulk Metallic Glass for Automotive Applications

2015 ◽  
Vol 1114 ◽  
pp. 68-75
Author(s):  
Mariana Lucaci ◽  
Delia Patroi ◽  
Violeta Tsakiris ◽  
Magdalena Valentina Lungu ◽  
Eugen Manta ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Metallic Glasses ◽  
Melt Spinning ◽  
Copper Mold ◽  
Technological Parameters ◽  
Glass Forming ◽  
Copper Mold Casting ◽  
Mold Casting ◽  
Melt Spin

Researches and developments were carried out for obtaining of bulk metallic glass (BMG) from the Fe-Cr-Ni-Si-B system. The used processing methods were copper mold casting and melt spinning method. The resulted materials are in form of sheets with sizes of 69.7 x 64 x 3/1.5 mm and of strips with thickness less than 50 microns, which were obtained by varying the melt spin technological parameters. The both processing variants are not suitable for obtaining such of alloy in bulk metallic glass form. Adding of zirconium to this alloy produces bulk metallic glasses only for the melt spin products. The DSC analysis emphases that the zirconium modified alloy processed by melt spinning method exhibits a high glass forming ability (GFA).

Preparation of Zr60Ni21Al19 bulk metallic glass and compression behavior under high pressure

2008 ◽  
Vol 23 (9) ◽  
pp. 2346-2349 ◽  
Author(s):  
G. Li ◽  
Q. Jing ◽  
T. Xu ◽  
L. Huang ◽  
R.P. Liu ◽  
...  
Keyword(s):  
High Pressure ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
High Strength ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Compression Behavior ◽  
Copper Mold Casting ◽  
Mold Casting ◽  
Diamond Anvil

Zr60Ni21Al19 metallic glass rod, with a diameter of 8 mm, is manufactured by copper mold casting. The as-cast bulk metallic glass (BMG) exhibits nearly zero plastic strain, but a high strength of 1.88 GPa. The compression behavior of this new zirconium-base ternary BMG under high pressure at ambient temperature in a diamond-anvil cell instrument has been unraveled using energy dispersive x-ray diffraction with a synchrotron radiation source. The investigation shows that the amorphous structure of Zr60Ni21Al19 is stable under pressures up to 24.5 GPa at room temperature. According to the Bridgman equation of state, the bulk modulus B0 = 96 GPa has been obtained.

Cu-Based Metallic Glass Matrix Composites with High Ductility

2004 ◽  
Vol 449-452 ◽  
pp. 441-444 ◽  
Author(s):  
Yu Chan Kim ◽  
Do Hyang Kim ◽  
Jae Chul Lee
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Glass Matrix ◽  
Matrix Composites ◽  
Copper Mold ◽  
Glass Matrix Composite ◽  
Injection Casting ◽  
Metallic Glass Matrix Composite ◽  
Composite Microstructure ◽  
Glass Matrix Composites

A composite microstructure consisted of µm-scale Ta-rich solid solution particles distributed in the bulk metallic glass matrix was successfully obtained by injection casting of the (Cu60Zr30Ti10)95Ta5alloy into a copper mold. The (Cu60Zr30Ti10)95Ta5bulk metallic glass matrix composite shows compressive strength of 2320 MPa and, in particular, a significantly improved plastic strain to failure of about 14.5%. The remarkable ductility improvement in the (Cu60Zr30Ti10)95Ta5composite could be explained by the presence of the highly ductile Tarich particles.

Fabrication of ternary Mg–Cu–Gd bulk metallic glass with high glass-forming ability under air atmosphere

2003 ◽  
Vol 18 (7) ◽  
pp. 1502-1504 ◽  
Author(s):  
H. Men ◽  
D. H. Kim
Keyword(s):  
Metallic Glass ◽  
Cooling Rate ◽  
Bulk Metallic Glass ◽  
Glass Formation ◽  
Glass Forming Ability ◽  
Casting Method ◽  
Glass Forming ◽  
Air Atmosphere ◽  
Mold Casting ◽  
Order Of Magnitude

A new Mg65Cu25Gd10 alloy having significantly improved glass-forming ability (GFA) has been developed. In this article, we show that the ternary Mg65Cu25Gd10 bulk metallic glass with diameter of at least 8 mm can successfully be fabricated by a conventional Cu-mold casting method in air atmosphere. The critical cooling rate for glass formation was estimated on the order of magnitude of approximately 1 K/s. When compared with the GFA of Mg65Cu25Y10 alloy, the significantly improved GFA of Mg65Cu25Gd10 alloy cannot be explained by ΔTx and Trg values.

Doubling the Critical Size for Bulk Metallic Glass Formation in the Mg–Cu–Y Ternary System

2005 ◽  
Vol 20 (9) ◽  
pp. 2252-2255 ◽  
Author(s):  
H. Ma ◽  
Q. Zheng ◽  
J. Xu ◽  
Y. Li ◽  
E. Ma
Keyword(s):  
Metallic Glass ◽  
Ternary System ◽  
Bulk Metallic Glass ◽  
Glass Formation ◽  
Composition Dependence ◽  
Critical Size ◽  
Glass Forming Ability ◽  
Glass Forming ◽  
Copper Mold Casting ◽  
Mold Casting

Mg−Cu−Y alloys with optimal glass forming ability have been found at off-eutectic compositions. The critical size for bulk metallic glass formation at the pinpointed compositions more than doubles that of the previously discovered eutectic Mg65Cu25Y10 alloy, leading to fully glassy rods with near-centimeter diameters in the ternary system upon copper mold casting. The result is a striking demonstration of the strong composition dependence of the glass forming ability, as well as of the need to scrutinize off-eutectic compositions. The implications of the discovery are discussed.

Ferromagnetic Characteristics of Bulk Fe63Co7Nb4Zr6B19Si1 Metallic Glass

2013 ◽  
Vol 873 ◽  
pp. 63-66
Author(s):  
Min Xu ◽  
Qun Jiao Wang
Keyword(s):  
Amorphous Alloy ◽  
Metallic Glass ◽  
Coercive Force ◽  
Saturation Magnetization ◽  
Crystallization Temperature ◽  
Annealing Treatment ◽  
Copper Mold ◽  
Copper Mold Casting ◽  
Mold Casting ◽  
Soft Ferromagnetic

By copper mold casting, a bulk Fe63Co7Nb4Zr6B19Si1 metallic glass was synthesized in the diameter of 2mm. The Fe-based amorphous alloy exhibits soft ferromagnetic characteristics with a saturation magnetization of 77Am2/kg and a saturated magnetostriction of 25.4×10-6. The saturation magnetization is reduced while the coercive force is slightly lowered by annealing treatment below the crystallization temperature. The devitrification gives rise to a remarkable enhancement both in saturation magnetization and coercive force.

A Centimeter-Size High Toughness Zr-Cu-Al-Nb Bulk Metallic Glass with Nano-Crystallization and Phase Separation

2018 ◽  
Vol 913 ◽  
pp. 668-673
Author(s):  
Chen Chen ◽  
Xiao Dong Jia ◽  
Hang Zhang ◽  
Ran Wei ◽  
Fu Shan Li
Keyword(s):  
Phase Separation ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Shear Bands ◽  
Glassy Matrix ◽  
Glass Forming ◽  
High Toughness ◽  
Copper Mold Casting ◽  
Novel Approach ◽  
Mold Casting

In this paper, a centimeter-size Zr-Cu-Al-Nb bulk metallic glass (BMG) with high notch toughness of 107±13 MPa∙m0.5 was designed and fabricated by copper mold casting. With 1% Nb substitution for Zr in Zr48Cu45Al7 glass forming alloy, the glass forming ability (GFA) and toughness of the BMG were enhanced significantly. The coexistence of nano-crystallization and phase separation in the glassy matrix was observed in Zr47Cu45Al7Nb1, which would possibly lead to the high toughness of this alloy due to the easy and populous nucleation of shear bands and the increasing resistance of shear band propagation. The influences of nano-crystallization and phase separation on the toughness of BMGs are discussed in detail. The strategy utilized in this study provides a novel approach in search for new BMGs with high toughness and good GFA.

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