Temperature dependence of mechanical properties in ultrathin Au films with and without passivation

Temperature and film thickness are expected to have an influence on the mechanical properties of thin films. However, mechanical testing of ultrathin metallic films at elevated temperatures is difficult, and few experiments have been conducted to date. Here, we present a systematic study of the mechanical properties of 80–500-nm-thick polycrystalline Au films with and without SiNx passivation layers in the temperature range from 123 to 473 K. The films were tested by a novel synchrotron-based tensile testing technique. Pure Au films showed strong temperature dependence above 373 K, which may be explained by diffusional creep. In contrast, passivated samples appeared to deform by thermally activated dislocation glide. The observed activation energies for both mechanisms are considerably lower than those for the bulk material, indicating that concomitant stress relaxation mechanisms are more pronounced in the thin film geometry.

Download Full-text

Mechanical Properties and Microstructure of AL(1wt%SI) And AL(1wt%SI, 0.5wt%CU) Thin Films. The Role of Diffusional Creep in the Tensile Stress Regime

MRS Proceedings ◽

10.1557/proc-356-435 ◽

1994 ◽

Vol 356 ◽

Author(s):

S. Bader ◽

E. M. Kalaugher ◽

E. Arzt

Keyword(s):

Mechanical Properties ◽

Relaxation Mechanism ◽

Diffusional Creep ◽

Stress Regime ◽

Cu Films ◽

Dislocation Glide ◽

Transmission Electron ◽

Diffusional Relaxation ◽

Coble Creep

AbstractThe microstructure and mechanical properties of hot (h) and cold (c) sputtered Al-lwt%Si and Al-lwt%Si-0.5wt%Cu films were studied using transmission electron microscopy and wafer curvature stress measurements.Stress/temperature curves of all films showed only slight differences in compression on healing once a stable grain size was established. However, on cooling several remarkable differences were observed. These observations cannot be explained by assuming dislocation glide/climb as the dominant relaxation mechanism. The results will be discussed in terms of grain boundary diffusional relaxation (Coble creep), which occurs in addition to dislocation glide.

Download Full-text

Violation of the T−1 Relationship in the Lattice Thermal Conductivity of Mg3Sb2 with Locally Asymmetric Vibrations

Research ◽

10.34133/2020/4589786 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Yifan Zhu ◽

Yi Xia ◽

Yancheng Wang ◽

Ye Sheng ◽

Jiong Yang ◽

...

Keyword(s):

Thermal Conductivity ◽

Temperature Dependence ◽

Lattice Thermal Conductivity ◽

Elevated Temperatures ◽

Low Frequency ◽

Strong Temperature Dependence ◽

Depth Analysis ◽

Force Profile ◽

Phonon Renormalization ◽

Increasing Temperature

Most crystalline materials follow the guidelines of T−1 temperature-dependent lattice thermal conductivity (κL) at elevated temperatures. Here, we observe a weak temperature dependence of κL in Mg3Sb2, T−0.48 from theory and T−0.57 from measurements, based on a comprehensive study combining ab initio molecular dynamics calculations and experimental measurements on single crystal Mg3Sb2. These results can be understood in terms of the so-called “phonon renormalization” effects due to the strong temperature dependence of the interatomic force constants (IFCs). The increasing temperature leads to the frequency upshifting for those low-frequency phonons dominating heat transport, and more importantly, the phonon-phonon interactions are weakened. In-depth analysis reveals that the phenomenon is closely related to the temperature-induced asymmetric movements of Mg atoms within MgSb4 tetrahedron. With increasing temperature, these Mg atoms tend to locate at the areas with relatively low force in the force profile, leading to reduced effective 3rd-order IFCs. The locally asymmetrical atomic movements at elevated temperatures can be further treated as an indicator of temperature-induced variations of IFCs and thus relatively strong phonon renormalization. The present work sheds light on the fundamental origins of anomalous temperature dependence of κL in thermoelectrics.

Download Full-text

Mechanical Properties of a β Containing Ti-Al-Cr-Alloy at Ambient and Elevated Temperatures

MRS Proceedings ◽

10.1557/proc-364-1017 ◽

1994 ◽

Vol 364 ◽

Author(s):

W. R. Chen ◽

J. Wang ◽

B. Zhang ◽

X. Wan ◽

W. J. Chen

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Ambient Temperature ◽

Strain Rate ◽

Temperature Dependence ◽

Elevated Temperatures ◽

High Tensile Strength ◽

Tial Alloys ◽

Β Phase ◽

Very High

AbstractThe mechanical properties of a β-containing Ti-Al-Cr alloy were investigated at ambient and elevated temperatures. The results show that the Ti-Al-Cr alloy containing the β phase has a very high tensile strength but a poor ductility at ambient temperature, and that higher ductility is obtained at high temperatures. The temperature dependence of mechanical properties is found to be sensitive to the strain rate during the test. Fractography shows that the fracture mode changes from fully brittle to ductile-brittle mixture with the increased temperature. All the results suggest that the triple-phased TiAl alloys (α2+β+γ) may have the combined mechanical properties of the dual-phased T13Al ((α2+β) and dual-phased TiAl (α2+γ) alloys.

Download Full-text

Microstructural Dependence of the Perpendicular Magnetic Anisotropy in Co-Pt Alloys

MRS Proceedings ◽

10.1557/proc-313-677 ◽

1993 ◽

Vol 313 ◽

Cited By ~ 6

Author(s):

E. E. Marinero ◽

R. F. C. Farrow ◽

G. R. Harp ◽

R. H. Geiss ◽

J. A. Bain ◽

...

Keyword(s):

Magnetic Anisotropy ◽

Temperature Dependence ◽

Elevated Temperatures ◽

Perpendicular Magnetic Anisotropy ◽

Strong Temperature Dependence ◽

Perpendicular Anisotropy ◽

Chemical Ordering ◽

Polycrystalline Alloys ◽

Out Of Plane ◽

Pt Alloys

ABSTRACTTo establish the structural origins of the perpendicular magnetic anisotropy in Co-Pt alloys, a variety of magnetic and structural characterization techniques have been utilized. We have determined that the development of out-of-plane magnetization in these alloys, strongly depends on growth temperature and in contrast to CO/Pt Multilayers, the highest anisotropics and coercivities are observed in polycrystalline alloys with negligible preferred crystallographic orientation. Lattice strain Measurements, surface roughness determination and crystal growth studies indicate that contributions from magnetostrictive and magnetostatic contributions to the perpendicular anisotropy in these alloys are not significant. H RTEM and synchrotron-based x-ray diffraction experiments, on the other hand, confirm the existence of ordered CoPt3 at elevated temperatures. We suggest that the strong temperature dependence of the perpendicular anisotropy is correlated to the onset of spontaneous chemical ordering during the growth which results in anisotropie pair ordering. A tentative model explaining this strong temperature dependence is described.

Download Full-text

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053188 ◽

1982 ◽

Vol 40 ◽

pp. 78-79

Author(s):

Kenneth H. Downing ◽

Robert M. Glaeser

Keyword(s):

Electron Beam ◽

Fatty Acid ◽

Inelastic Scattering ◽

Temperature Dependence ◽

Structural Damage ◽

Direct Result ◽

Second Step ◽

Strong Temperature Dependence ◽

Electron Dose ◽

Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

Download Full-text

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009292x ◽

1976 ◽

Vol 34 ◽

pp. 592-593

Author(s):

Ernest L. Hall ◽

J. B. Vander Sande

Keyword(s):

Mechanical Properties ◽

Single Crystal ◽

Dislocation Structure ◽

Room Temperature ◽

Elevated Temperatures ◽

Strain Curve ◽

Optical Devices ◽

Semiconductor Compound ◽

Wide Range ◽

Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

Download Full-text

CARLSON ALLOY C600 and C600 ESR

Alloy Digest ◽

10.31399/asm.ad.ni0470 ◽

1994 ◽

Vol 43 (11) ◽

Keyword(s):

Mechanical Properties ◽

Solid Solution ◽

Fracture Toughness ◽

Cold Working ◽

Elevated Temperatures ◽

High Strength ◽

Heat Treating ◽

Solid Solution Alloy ◽

Resistance To Oxidation ◽

Good Workability

Abstract CARLSON ALLOYS C600 AND C600 ESR have excellent mechanical properties from sub-zero to elevated temperatures with excellent resistance to oxidation at high temperatures. It is a solid-solution alloy that can be hardened only by cold working. High strength at temperature is combined with good workability. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: Ni-470. Producer or source: G.O. Carlson Inc.

Download Full-text

BRUSH ALLOY 3

Alloy Digest ◽

10.31399/asm.ad.cu0454 ◽

1983 ◽

Vol 32 (3) ◽

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Corrosion Resistance ◽

Physical Properties ◽

Copper Alloy ◽

Elevated Temperatures ◽

Physical And Mechanical Properties ◽

Heat Treating ◽

Good Resistance ◽

Good Corrosion Resistance

Abstract BRUSH Alloy 3 offers the highest electrical and thermal conductivity of any beryllium-copper alloy. It possesses an excellent combination of moderate strength, good corrosion resistance and good resistance to moderately elevated temperatures. Because of its unique physical and mechanical properties, Brush Alloy 3 finds widespread use in welding applications (RWMA Class 3), current-carrying springs, switch and instrument parts and similar components. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as casting, forming, heat treating, machining, joining, and surface treatment. Filing Code: Cu-454. Producer or source: Brush Wellman Inc..

Download Full-text

NICROFER 6023

Alloy Digest ◽

10.31399/asm.ad.ni0314 ◽

1985 ◽

Vol 34 (5) ◽

Keyword(s):

Mechanical Properties ◽

Elevated Temperatures ◽

Iron Alloy ◽

Heat Treating ◽

Chemical Equipment ◽

Good Resistance ◽

Nickel Chromium ◽

Power Plant Equipment ◽

Resistance To Oxidation ◽

Plant Equipment

Abstract NICROFER 6023 is a nickel-chromium-iron alloy containing small quantities of aluminum. It has excellent resistance to oxidation at high temperatures, good resistance in oxidizing sulfur-bearing atmospheres and good resistance to carburizing conditions. The alloy has good mechanical properties at room and elevated temperatures. Its applications include heat treating furnace equipment, chemical equipment in various industries, and power plant equipment. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-314. Producer or source: Vereingte Deutsche Metallwerke AG.

Download Full-text

ESCO ALLOY 72

Alloy Digest ◽

10.31399/asm.ad.co0048 ◽

1966 ◽

Vol 15 (5) ◽

Keyword(s):

Mechanical Properties ◽

Thermal Shock Resistance ◽

Elevated Temperatures ◽

Base Alloy ◽

Heat Treating ◽

Corrosive Media ◽

Temperature Performance ◽

Cobalt Base Alloy ◽

Shock Resistance ◽

Cobalt Base

Abstract ESCO Alloy 72 is a cobalt-base alloy having high corrosion, heat and thermal shock resistance. It is recommended for applications requiring good mechanical properties at elevated temperatures and/or in corrosive media. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Co-48. Producer or source: ESCO Corporation.

Download Full-text