Influence of bias voltage on residual stresses and tribological properties of TiAlVN-coatings at elevated temperatures

One possibility to improve the fatigue life and strength of metallic materials is shot peening. However, at elevated temperatures, the induced residual stresses may relax. To investigate the influence of shot peening on high-temperature fatigue behavior, isothermal fatigue tests were conducted on shot-peened and untreated samples of gamma TiAl 48-2-2 at 750 °C in air. The shot-peened material was characterized using EBSD, microhardness, and residual stress analyses. Shot peening leads to a significant increase in surface hardness and high compressive residual stresses near the surface. Both effects may have a positive influence on lifetime. However, it also leads to surface notches and tensile residual stresses in the bulk material with a negative impact on cyclic lifetime. During fully reversed uniaxial tension-compression fatigue tests (R = −1) at a stress amplitude of 260 MPa, the positive effects dominate, and the fatigue lifetime increases. At a lower stress amplitude of 230 MPa, the negative effect of internal tensile residual stresses dominates, and the lifetime decreases. Shot peening leads to a transition from surface to volume crack initiation if the surface is not damaged by the shots.

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Influence of Applied Bias Voltage on the Composition, Structure, and Properties of Ti:Si-Codoped a-C:H Films Prepared by Magnetron Sputtering

Journal of Nanomaterials ◽

10.1155/2014/937068 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Jinlong Jiang ◽

Qiong Wang ◽

Yubao Wang ◽

Zhang Xia ◽

Hua Yang ◽

...

Keyword(s):

Mechanical Properties ◽

Surface Roughness ◽

Magnetron Sputtering ◽

Bias Voltage ◽

Tribological Properties ◽

Structure And Properties ◽

Applied Bias ◽

Applied Bias Voltage ◽

Methane Mixture ◽

Composition Structure

The titanium- and silicon-codoped a-C:H films were prepared at different applied bias voltage by magnetron sputtering TiSi target in argon and methane mixture atmosphere. The influence of the applied bias voltage on the composition, surface morphology, structure, and mechanical properties of the films was investigated by XPS, AFM, Raman, FTIR spectroscopy, and nanoindenter. The tribological properties of the films were characterized on an UMT-2MT tribometer. The results demonstrated that the film became smoother and denser with increasing the applied bias voltage up to −200 V, whereas surface roughness increased due to the enhancement of ion bombardment as the applied bias voltage further increased. The sp3carbon fraction in the films monotonously decreased with increasing the applied bias voltage. The film exhibited moderate hardness and the superior tribological properties at the applied bias voltage of −100 V. The tribological behaviors are correlated to the H/E or H3/E2ratio of the films.

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A Study on Mechanical and Tribological Properties of Hot Pressed Al2O3/ZrO2/h-BN/TiO2 Composites

Materials Science Forum ◽

10.4028/www.scientific.net/msf.695.417 ◽

2011 ◽

Vol 695 ◽

pp. 417-420 ◽

Cited By ~ 1

Author(s):

Hyun Hwi Lee ◽

Seung Ho Kim ◽

Bhupendra Joshi ◽

Soo Wohn Lee

Keyword(s):

Tribological Properties ◽

Ceramic Composite ◽

Elevated Temperatures ◽

Cutting Tools ◽

High Hardness ◽

High Melting Point ◽

Corrosion Resistant ◽

Mechanical And Tribological Properties ◽

Chemical Inertness ◽

Corrosion Resistant Coatings

Oxide ceramics such as alumina and zirconia are industrially utilized as cutting tools, a variety of bearings, biomaterials, and thermal and corrosion-resistant coatings due to their high hardness, chemical inertness, high melting point, and ability to retain mechanical strength at elevated temperatures. In this research, the effect of other ceramic additives (TiO2) and h-BN within alumina(α-Al2O3) and yttria-stabilized tetragonal (Y-TZP) composite was studied with respect to the mechanical and tribological properties. The lowest coefficient of frction of 0.45 was observed for the ZTA ceramic composite with hBN-TiO2. The highest hardness, fracture toughness and flexural strength were obtained as 15.7GPa, 5.2MPam-1/2, 712MPa, respectively.

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Thermal Stability of Residual Stresses in Differently Deep Rolled Surface Layers of Steel SAE 1045

Journal of Materials Engineering and Performance ◽

10.1007/s11665-021-05798-x ◽

2021 ◽

Author(s):

Stephanie Saalfeld ◽

Thomas Wegener ◽

Berthold Scholtes ◽

Thomas Niendorf

Keyword(s):

Thermal Stability ◽

Elevated Temperature ◽

Residual Stresses ◽

Elevated Temperatures ◽

Fatigue Behavior ◽

Decisive Role ◽

Deep Rolling ◽

Material Conditions ◽

The Stability ◽

Thermal Stability Of

AbstractThe stability of compressive residual stresses generated by deep rolling plays a decisive role on the fatigue behavior of specimens and components, respectively. In this regard, deep rolling at elevated temperature has proven to be very effective in stabilizing residual stresses when fatigue analysis is conducted at ambient temperature. However, since residual stresses can be affected not only by plastic deformation but also when thermal energy is provided, it is necessary to analyze the influence of temperature and time on the relaxation behavior of residual stresses at elevated temperature. To evaluate the effect of deep rolling at elevated temperatures on stability limits under thermal as well as combined thermo-mechanical loads, the present work introduces and discusses the results of investigations on the thermal stability of residual stresses in differently deep rolled material conditions of the steel SAE 1045.

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PREDICTION OF PEEK RESIN PROPERTIES FOR PROCESSING MODELING USING MOLECULAR DYNAMICS

10.12783/asc36/35813 ◽

2021 ◽

Author(s):

KHATEREH KASHMARI ◽

PRATHAMESH DESHPANDE ◽

SAGAR PATIL ◽

SAGAR SHAH ◽

MARIANNA MAIARU ◽

...

Keyword(s):

Molecular Dynamics ◽

Residual Stresses ◽

Crystallization Kinetics ◽

Material Properties ◽

Elevated Temperatures ◽

Processing Parameters ◽

Thermomechanical Properties ◽

Volumetric Shrinkage ◽

Processing Temperature ◽

Wide Range

Polymer Matrix Composites (PMCs) have been the subject of many recent studies due to their outstanding characteristics. For the processing of PMCs, a wide range of elevated temperatures is typically applied to the material, leading to the development of internal residual stresses during the final cool-down step. These residual stresses may lead to net shape deformations or internal damage. Also, volumetric shrinkage, and thus additional residual stresses, could be created during crystallization of the semi-crystalline thermoplastic matrix. Furthermore, the thermomechanical properties of semi-crystalline polymers are susceptible to the crystallinity content, which is tightly controlled by the processing parameters (processing temperature, temperature holding time) and material properties (melting and crystallization temperatures). Hence, it is vital to have a precise understanding of crystallization kinetics and its impact on the final component's performance to accurately predict induced residual stresses during the processing of these materials. To enable multi-scale process modeling of thermoplastic composites, molecular-level material properties must be determined for a wide range of crystallinity levels. In this study, the thermomechanical properties and volumetric shrinkage of the thermoplastic Poly Ether Ether Ketone (PEEK) resin are predicted as a function of crystallinity content and temperature using molecular dynamics (MD) modeling. Using crystallization-kinetics models, the thermo-mechanical properties are directly related to processing time and temperature. This research can ultimately predict the residual stress evolution in PEEK composites as a function of processing parameters.

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The influence of SrSO4 on the tribological properties of NiCr–Al2O3 cermet at elevated temperatures

Ceramics International ◽

10.1016/j.ceramint.2013.10.035 ◽

2014 ◽

Vol 40 (2) ◽

pp. 2799-2807 ◽

Cited By ~ 10

Author(s):

Feng Liu ◽

Gewen Yi ◽

Wenzhen Wang ◽

Yu Shan ◽

Junhong Jia

Keyword(s):

Tribological Properties ◽

Elevated Temperatures

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The Effect of Elemental Composition and Nanostructure of Multilayer Composite Coatings on Their Tribological Properties at Elevated Temperatures

10.5772/intechopen.93973 ◽

2020 ◽

Author(s):

Alexey Vereschaka ◽

Sergey Grigoriev ◽

Vladimir Tabakov ◽

Mars Migranov ◽

Nikolay Sitnikov ◽

...

Keyword(s):

Elemental Composition ◽

Coefficient Of Friction ◽

Tribological Properties ◽

Elevated Temperatures ◽

Composite Coatings ◽

Multilayer Composite ◽

The Coefficient Of Friction ◽

The Relationship ◽

Tribological Parameters ◽

Adhesion Component

The chapter discusses the tribological properties of samples with multilayer composite nanostructured Ti-TiN-(Ti,Cr,Al,Si)N, Zr-ZrN-(Nb,Zr,Cr,Al)N, and Zr-ZrN-(Zr,Al,Si)N coatings, as well as Ti-TiN-(Ti,Al,Cr)N, with different values of the nanolayer period λ. The relationship between tribological parameters, a temperature varying within a range of 20–1000°C, and λ was investigated. The studies have found that the adhesion component of the coefficient of friction (COF) varies nonlinearly with a pronounced extremum depending on temperature. The value of λ has a noticeable influence on the tribological properties of the coatings, and the nature of the mentioned influence depends on temperature. The tests found that for the coatings with all studied values of λ, an increase in temperature first caused an increase and then a decrease in COF.

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The tribological properties of Ti3SiC2/Cu/Al/SiC composite at elevated temperatures

Tribology International ◽

10.1016/j.triboint.2016.09.008 ◽

2016 ◽

Vol 104 ◽

pp. 294-302 ◽

Cited By ~ 12

Author(s):

Wentao Dang ◽

Shufang Ren ◽

Jiansong Zhou ◽

Youjun Yu ◽

Lingqian Wang

Keyword(s):

Tribological Properties ◽

Elevated Temperatures

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Tribological Properties of Hot-Pressed SrSO4 Ceramic at Elevated Temperatures in Dry Sliding Against Alumina Ball

Journal of Tribology ◽

10.1115/1.4042679 ◽

2019 ◽

Vol 141 (5) ◽

Author(s):

Chong-Chong Mao ◽

Yu-Feng Li

Keyword(s):

Tribological Properties ◽

Room Temperature ◽

Elevated Temperatures ◽

Testing Temperature ◽

Dry Sliding ◽

Potential Candidate ◽

Friction Behavior ◽

Wear Rates ◽

Brittle To Ductile Transition ◽

Lubricating Film

SrSO4 ceramic was prepared by hot-pressed sintering and its friction behavior was investigated against the Al2O3 ball under the dry sliding condition from room temperature to 800 °C. From room temperature to 400 °C, the tribological properties of SrSO4 ceramic are quite poor with the friction coefficients of 0.65–0.83 and the wear rates of about 10−3 mm3/Nm. With the testing temperature increasing to 600 °C and 800 °C, a brittle to ductile transition of SrSO4 takes place because of the activated slip systems. The friction coefficient and wear rate of SrSO4 ceramic also obviously decrease to 0.37 and about 10−4 mm3/Nm at 800 °C. The significant improvement of the tribological properties is ascribed to the formation of a smooth and continuous SrSO4 lubricating film with excellent ductility and low shear strength at elevated temperature. SrSO4 is considered to be a potential candidate for high-temperature solid lubricant with excellent lubricity.

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