Thermal-tempering analysis of bulk metallic glass plates using an instant-freezing model

Aydıner, C. Can; Ü:Ustü:UndaG, E.; Hanan, Jay C.

doi:10.1007/s11661-001-1023-8

Cited by 17 publications

(16 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We can now match all experimental data and obtain strong localization in agreement with experimental observations [1]. We have also developed specialized strain-localization finite elements that match experimental data on dynamic shear band propagation [2][3][4].…”

Section: Discussionmentioning

confidence: 60%

“…Third, elastic modulus and Poisson's ratio differ depending on the cooling rates of samples which indicates that the sound propagation velocities of plane waves (longitudinal and transverse) in the samples are significantly different depending on the different cooling rate during processing. Binary BMG Alloys It has been proposed as an empirical rule that in order to form a bulk amorphous structure a metallic system must comprise at least three elements [1]. Nevertheless, in an attempt to establish a good starting point for new rnulti-component bulk metallic glasses, several binary alloys were found to form bulk amorphous structures by themselves using the regular copper mold casting method, although they only consist of two elements.…”

Section: Ni-based Alloysmentioning

confidence: 99%

See 1 more Smart Citation

Caltech Center for Structural and Amorphous Metals

Johnson¹,

Conner²

2005

View full text Add to dashboard Cite

The program may be divided into several components: alloy development, mechanical characterization, and theory. The alloy development segment included modeling of phase diagrams to predict glass forming compositions, computer simulation of flow to develop advanced forming methods, rheology measurement, and thorough characterization of the all program alloys through high-energy x-ray analysis. The mechanical characterization program consisted of studies of fracture, fatigue and determination of the appropriate flow laws (e.g., Mohr-Coulomb vs. von Mises), development of constitutive laws, and shear band formation. The third focus, computer simulation, covered length scales from molecular dynamics and first principle quantum mechanics through finite element analysis to describe shear band fbrmation under high strain rate loading.Several new glass-forming alloy systems were developed, including new Cu-based, Ni-based, and Ti-Zr-based Alloy Classes with "cm" casting thickness and a monolithic Ni-Pt-base bmg with Kic = 85 MPa-m/ 2 , These systems include Ni-Nb-Ta-Sn glasses with 3mm critical casting thickness, Ni-Ti-Zr-Al ductile glasses with 6mm critical casting thickness, new ductile Cubased alloys with 15mm critical casting thickness, and new Hf-Zr-Co-Al glasses with 12mm critical casting thickness and density of 11 grams/cm 3 . Lightweight amorphous alloys consisted of new Ti-based composites with densities of 4.5-5 g/cm 3 , strength exceeding 2 GPa, 2-cm casting thickness, high toughness and excellent ductility, and ductile magnesium alloys with 2-mm casting thickness. We also synthesized lightweight BMG foams and cellular structures with novel properties.Fundamental theory and computational models for rheological and mechanical behavior were established and validated. We have characterized the flow vs. temperature, strain rate, and 6 loading conditions, and developed empirical flow laws which accurately describe flow and deformation. These flow laws were incorporated into process models (Flow 3D, Femlab and Moldflow) and mechanical FEA models were developed to describe deformation of foams, plates in bending, and high strain-rate deformation. The theory is presently being used to predict, model and design practical materials for engineering performance.Major effort has focused on developing first thermodynamic descriptions of the 5 constituent quaternaries and then the quinary Al-Cu-Ni-Ti-Zr system. Preliminary results show alloys predicted by the model do indeed form bulk glasses. Thermodynamic descriptions of the constituent quatemaries of the six-component Al-Cu-Ni-Ti-Zr-Si system and then the description of this six-component system are being developed.A new microscopic theory of glasses and liquids was developed based on models of the potential energy landscape of a glass. This theory is based on empirical data, results of MD simulations, and analytic methods. The theory can predict thermal properties, liquid theology, and mechanical properties such as strength, toughness and ductility. This is a fundame...

show abstract

Section: Discussionmentioning

confidence: 60%

Section: Ni-based Alloysmentioning

confidence: 99%

Caltech Center for Structural and Amorphous Metals

Johnson¹,

Conner²

2005

View full text Add to dashboard Cite

show abstract

“…Its variation was more pronounced (about 3%) for the "Elastic SS" case. This insensitivity is attributed to the saturation of the temper level at these high values of heat transfer coefficient [3,4].…”

Section: Resultsmentioning

confidence: 99%

“…This is a wellestablished process in silicate glasses [3]. Thermal tempering in BMGs has been recently investigated for the first time by Aydiner et al in a series of systematic studies [4][5][6]. Aydiner et al showed that the thermoviscoelastic model they developed earlier can predict residual stresses within 15-30% of experimental data [6].…”

Section: Introductionmentioning

confidence: 99%

Residual stresses in a bulk metallic glass–stainless steel composite

Aydıner

Üstündag

Clausen

et al. 2005

Materials Science and Engineering: A

View full text Add to dashboard Cite

“…[13] As stated earlier, quench stresses are an inevitable outcome of metallic glass production, while thermal tempering is regularly used to introduce a beneficial residual stress profile (compressive surface residual stresses balanced by the midplane tension) into silicate glasses [14] and BMGs. [15,16] Favorable compressive residual stresses can also be generated by introducing surface plastic deformation, for example, by shot peening (bombarding the surface with small ''shot''). This surface engineering process can enhance the ductility of BMGs, depending on the load case.…”

Section: Introductionmentioning

confidence: 99%

Mapping Residual Stress Distributions at the Micron Scale in Amorphous Materials

Winiarski

Langford

Tian

et al. 2009

Metall Mater Trans A

View full text Add to dashboard Cite

Residual stresses in crystalline or glassy materials often play a key role in the performance of advanced devices and components. However, stresses in amorphous materials cannot easily be determined at the micron scale by diffraction, or by other conventional laboratory methods. In this article, a technique for mapping residual stress profiles in amorphous materials with high spatial definition is presented. By applying a focused ion beam (FIB)-based semidestructive mechanical relaxation method, the stresses are mapped in a peened and fatigued bulk metallic glass (BMG) (Zr 50 Cu 40 Al 10 at. pct). The residual stresses are inferred using finite element analysis (FEA) of the surface relaxations, as measured by digital image correlation (DIC), that occur when a microslot is micromachined by FIB. Further, we have shown that acceptable accuracy can in most cases be achieved using a simple analytical model of the slot. It was found that the fatigue cycling significantly changes the distribution of compressive residual stresses with depth in the plastically deformed surface layer. Our observations point to the scalability of this method to map residual stresses in volumes as small as 1 9 1 9 0.2 lm 3 or less.

show abstract

Thermal-tempering analysis of bulk metallic glass plates using an instant-freezing model

Cited by 17 publications

References 23 publications

Caltech Center for Structural and Amorphous Metals

Caltech Center for Structural and Amorphous Metals

Residual stresses in a bulk metallic glass–stainless steel composite

Mapping Residual Stress Distributions at the Micron Scale in Amorphous Materials

Contact Info

Product

Resources

About