scholarly journals Mechanical performance and fracture behavior of Fe41Co7Cr15Mo14Y2C15B6 bulk metallic glass

2007 ◽  
Vol 22 (2) ◽  
pp. 358-363 ◽  
Author(s):  
Q.J. Chen ◽  
J. Shen ◽  
D.L. Zhang ◽  
H.B. Fan ◽  
J.F. Sun
Keyword(s):  
Uniaxial Compression ◽  
Fracture Mode ◽  
Mechanical Performance ◽  
Glassy Alloy ◽  
Fracture Mechanisms ◽  
Hardness Tests ◽  
Indentation Tests ◽  
Bulk Glassy Alloy ◽  
Impact Bending ◽  
Micrometer Scale

The mechanical properties of a new Fe41Co7Cr15Mo14Y2C15B6 bulk glassy alloy were studied by impact bending, compression, and hardness tests carried out at room temperature. The compressive fracture strength, elastic strain to fracture, Young’s modulus and Vickers hardness were measured to be 3.5 GPa, 1.5%, 265 GPa, and 1253 kg mm−2, respectively. The fracture mode of the glassy alloy under uniaxial compression is different from those of other bulk metallic glasses in that this fracture mode causes the samples to be broken, in an exploding manner, into a large number of micrometer-scale pieces. The fracture mechanisms of this bulk glassy alloy under bending and uniaxial compression are discussed based on the observation of the fracture surfaces. Vickers indentation tests indicate that the structure of the glassy ingot may be inhomogeneous.

Enhancement of plasticity in Ti-rich Ti–Zr–Be–Cu–Ni–Ta bulk glassy alloy via introducing the structural inhomogeneity

2008 ◽  
Vol 23 (11) ◽  
pp. 2984-2989 ◽  
Author(s):  
Jin Man Park ◽  
Do Hyang Kim ◽  
Ki Buem Kim ◽  
Eric Fleury ◽  
Min Ha Lee ◽  
...  
Keyword(s):  
Glassy Alloy ◽  
Shear Bands ◽  
Structural Inhomogeneity ◽  
Glassy Matrix ◽  
Premature Failure ◽  
Glassy Alloys ◽  
Alloy Chemistry ◽  
Bulk Glassy Alloy ◽  
Heterogeneous Microstructures ◽  
Micrometer Scale

The effect of microstructural inhomogeneities with different length scale on the plasticity of (Ti45Zr16Be20Cu10Ni9)100–xTax (x = 0, 5, and 10) bulk glassy alloys has been studied. The formation of specific heterogeneous microstructures with a different type of structural inhomogeneity, i.e., short-/medium-range ordered clusters or micrometer-scale ductile dendrites combined with a glassy matrix, evolved by appropriately tuning the alloy chemistry, improves the room temperature plasticity up to ∼12.5% and ∼15%, respectively. The pronouncedly enhanced plasticity is mainly attributed to the retardation of shear localization and multiplication of shear bands by controlling the plastic and failure instabilities otherwise responsible for premature failure.

Influence of Melt Temperature on Compressive Plasticity of a Cu-Zr-Al Bulk Metallic Glass

2010 ◽  
Vol 146-147 ◽  
pp. 517-521
Author(s):  
Sheng Hui Xie ◽  
Xie Rong Zeng ◽  
Dong Ju Fu ◽  
Lei Zhao ◽  
Qiang Hu
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Metallic Glasses ◽  
Mechanical Performance ◽  
Casting Temperature ◽  
Thermal And Mechanical Properties ◽  
Micro Hardness ◽  
Melt Temperature ◽  
Hardness Tests ◽  
Important Solution

Cu47.5Zr47.5Al5 bulk metallic glasses (BMGs) were cast from the melt temperature 1143 to 1373 K. The structure, thermal and mechanical properties of the BMGs were investigated by XRD, DSC, HRTEM, dilatometric measurements, micro-hardness tests and uniaxial compression. The results indicate that the microstructure and mechanical performance of BMGs are closely affected by the casting temperature. Proper casting temperature ensures the BMGs with large relaxed excess free volume (REFV) and nano-crystallites, which favor the plastic deformation in Cu47.5Zr47.5Al5 BMGs. Regulating the preparing parameters is an important solution to good plasticity in BMGs.

Comparison of mechanical properties of thermally modified wood at growth ring and cell wall level by means of instrumented indentation tests

Holzforschung ◽  
2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Stefanie Stanzl-Tschegg ◽  
Wilfried Beikircher ◽  
Dieter Loidl
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Thermal Treatment ◽  
Mechanical Performance ◽  
Growth Ring ◽  
Beech Wood ◽  
Thermal Modification ◽  
Wood Structure ◽  
Instrumented Indentation ◽  
Indentation Tests

Abstract Thermal modification is a well established method to improve the dimensional stability and the durability for outdoor use of wood. Unfortunately, these improvements are usually accompanied with a deterioration of mechanical performance (e.g., reduced strength or higher brittleness). In contrast, our investigations of the hardness properties in the longitudinal direction of beech wood revealed a significant improvement with thermal modification. Furthermore, we applied instrumented indentation tests on different hierarchical levels of wood structure (growth ring and cell wall level) to gain closer insights on the mechanisms of thermal treatment of wood on mechanical properties. This approach provides a variety of mechanical data (e.g., elastic parameters, hardness parameters, and viscoelastic properties) from one single experiment. Investigations on the influence of thermal treatment on the mechanical properties of beech revealed similar trends on the growth ring as well as the on the cell wall level of the wood structure.

Indentation Tests for Sintered Silver in Die-Attach Interconnection After Thermal Cycling

2021 ◽  
Author(s):  
Fei Qin ◽  
Shuai Zhao ◽  
Yanwei Dai ◽  
Lingyun Liu ◽  
Tong An ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
Silver Layer ◽  
Thermal Cycles ◽  
Nano Indentation ◽  
Die Attach ◽  
Indentation Tests ◽  
Sintered Silver

Abstract Thermo-mechanical reliability assessment for sintered silver is a crucial issue as sintered silver is a promising candidate of die-attachment materials for power devices. In this paper, the nano-indentation tests are performed for sintered silver in typical die-attach interconnection under different thermal cycles. Based on thermal cycling test, the Young's modulus and hardness of sintered silver layer have been presented. It is found that the Young's modulus and hardness of sintered silver layer changes slightly although the microstructure of sintered silver also presents some variations. The stress and strain curves for different thermal cycling tests for sintered silver based on reverse analysis of nano-indentation are also given. The results show that the elastoplastic constitutive equations change significantly after thermal cycling tests, and the yielding stress decreases remarkably after 70 thermal cycles. The experimental investigation also show that the cracking behaviors of sintered silver depends on its geometry characteristics, which implies that the possible optimization of sintered silver layer could enhance its thermo-mechanical performance.

Further analysis of the size effect in indentation hardness tests of some metals

1995 ◽  
Vol 10 (11) ◽  
pp. 2908-2915 ◽  
Author(s):  
M. Atkinson
Keyword(s):  
Size Effect ◽  
Strain Hardening ◽  
Indentation Size Effect ◽  
Plastic Hinge ◽  
Small Scale ◽  
Indentation Hardness ◽  
Vickers Indentation ◽  
Indentation Size ◽  
Hardness Tests ◽  
Indentation Tests

The variation of apparent hardness observed in previously reported Vickers indentation tests of metals is reexamined. Common deseriptions of the effect are shown to be inaccurate: the variation of apparent hardness is monotonic but not simple. The effect is consistent with varying size of a previously postulated “plastic hinge” at the perimeter of the indent. This complexity confers uncertainty on the estimation of characteristic macrohardness from small scale tests. Association of the indentation size effect with friction and with strain hardening is confirmed.

Investigation of a ductile and corrosion-resistant Pd79Au1.5Ag3Si16.5 bulk metallic glass

2010 ◽  
Vol 25 (10) ◽  
pp. 1943-1949
Author(s):  
N. Chen ◽  
C.L. Qin ◽  
G.Q. Xie ◽  
D.V. Louzguine-Luzgin ◽  
A. Inoue
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Glassy Phase ◽  
Glassy Alloy ◽  
High Thermal Stability ◽  
Corrosion Resistant ◽  
Excellent Corrosion Resistance ◽  
Potential Applications ◽  
Bulk Glassy Alloy ◽  
High Degree

A new Pd79Au1.5Ag3Si16.5 bulk metallic glass was successfully synthesized in a maximum casting thickness range to 3 mm. Upon heating, the single glassy phase decomposed into Pd-rich crystalline phases and a Si-rich amorphous phase due to solute partitioning. In addition to high thermal stability, this bulk glassy alloy also exhibited a high degree of ductility and excellent corrosion resistance, showing potential applications as biomaterials.

Similarity analysis of creep indentation tests

1992 ◽  
Vol 436 (1898) ◽  
pp. 617-630 ◽  
Keyword(s):  
Auxiliary Problem ◽  
Secondary Creep ◽  
Depth Of Penetration ◽  
Similarity Transformations ◽  
Similarity Relations ◽  
Hardness Tests ◽  
Wide Range ◽  
Indentation Tests ◽  
Nonlinear Elastic ◽  
Physical Quantities

The general theory of axisymmetric hardness tests on nonlinear media is approached from the standpoint of similarity transformations. It is shown how an entire process of indentation can be made to depend on the solution of just one boundary-value problem in scaled variables and with a fixed geometry. Once this single auxiliary solution has been obtained, the values of all physical quantities in the original problem can be generated readily at any stage without further numerical error. Even by themselves the similarity relations provide valuable information about (for example) an invariant connection between the depth of penetration and the radius of contact, or about the variation of penetration with time in a creep test under dead load. Two kinds of material behaviour are considered: (a) nonlinear elastic (modelling strain-hardening plasticity) and (b) nonlinear viscous (modelling secondary creep). In either category the constitutive specification is sufficiently flexible to represent a wide range of actual responses in the context of hardness testing. The analysis for case (a) extends a theory of ball indentation by Hill et al . to a class of indenters with shapes varying from flat to conical. It also prepares the ground for case (6) which is more difficult and calls for a quite different auxiliary problem.

A New Fe-based Bulk Glassy Alloy with Outstanding Mechanical Properties

2004 ◽  
Vol 16 (23-24) ◽  
pp. 2189-2192 ◽  
Author(s):  
A. Inoue ◽  
B. L. Shen
Keyword(s):  
Mechanical Properties ◽  
Glassy Alloy ◽  
Bulk Glassy Alloy
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