Residual Stress Effects on the Fracture of Tantalum Nitride Films

1996 ◽  
Vol 458 ◽  
Author(s):  
N. R. Moody ◽  
R. Q. Hwang ◽  
J. E. Angelo ◽  
S. Venkataraman ◽  
W. W. Gerberich
Keyword(s):  
Residual Stress ◽  
Compressive Residual Stress ◽  
Tantalum Nitride ◽  
Stress Effects ◽  
Sputter Deposited ◽  
Parallel Arrays ◽  
Scratch Tests ◽  
Single Crystal Sapphire ◽  
Compressive Residual Stresses ◽  
Deposited Films

ABSTRACTIn this study, continuous microscratch testing was used to determine the effects of compressive residual stresses on the fracture of thin tantalum nitride films. The films were sputter deposited at room temperature onto single crystal sapphire substrates to a thickness of 600 nm. Some films were left in the as-deposited condition while the remaining films were vacuum annealed at 300°C. The only discernible change in structure was a surface rearrangement of atoms into parallel arrays of striations on the vacuum annealed samples revealing a high compressive residual stress in the films. These stresses had a strong effect on fracture as shown by the as-deposited films which buckled readily during scratch tests forming uniform-width and circular blisters while the vacuum annealed films exhibited a much lower susceptibility to fracture. Application of mechanics-based models for film buckling defined the levels of compressive residual stress and their effect on interfacial fracture.

Aging Effects on the Durability of Tantalum Nitride Films

1997 ◽  
Vol 505 ◽  
Author(s):  
N. R. Moody ◽  
D. Medlin ◽  
D. Boehme ◽  
D. Norwood
Keyword(s):  
Sputter Deposition ◽  
Tantalum Nitride ◽  
X Ray Diffraction ◽  
Aging Effects ◽  
Subsequent Aging ◽  
X Ray ◽  
Sputter Deposited ◽  
Compressive Residual Stresses ◽  
Deposited Films

ABSTRACTIn this study, nanoindentation and nanoscratch testing were used to determine the effects of annealing and long term aging on the properties and fracture resistance of thin tantalum nitride resistor films on aluminum nitride substrates. These films were sputter-deposited to a thickness of 440 nm. Some films were left in the as-deposited condition while others were annealed or annealed and then aged. X-ray diffraction revealed that sputter deposition created high compressive residual stresses in the as-deposited films which were partially relieved by annealing. Subsequent aging of the annealed films had no effect on residual stress levels. Nanoindentation showed that mechanical properties were unchanged after annealing and after annealing and aging. However, nanoscratch testing showed that annealing markedly reduced the susceptibility to catastrophic failure with no further changes discernible after aging.

Residual Stress, Fracture, and Adhesion in Sputter-Deposited Molybdenum Films

1988 ◽  
Vol 119 ◽  
Author(s):  
D. M. Mattox ◽  
R. E. Cuthrell
Keyword(s):  
Residual Stress ◽  
Strain Energy ◽  
Pressure Cycling ◽  
Stress Anisotropy ◽  
Magnetron Sputter Deposition ◽  
Magnetron Sputter ◽  
Sputter Deposited ◽  
Film Substrate ◽  
Deposited Films ◽  
Deposition Conditions

AbstractAtomistically deposited films may form with high residual stresses which may be either tensile or compressive in nature. These film stresses represent stored strain energy which may affect the adhesion of the film-substrate couple and in the limit may cause spontaneous fracture at or near the film-substrate interface (loss of adhesion). In the post cathode magnetron sputter deposition of molybdenum films, we have found that the intrinsic film stresses are generally anisotropic and may easily exceed the fracture or adhesive strength of the film-substrate couple. The residual stress anisotropy in the film is dependent on the orientation with respect to the post cathode and the magnitude and nature of the stresses are very dependent on the deposition conditions, particularly gas pressure during sputtering. By using a pressure-cycling technique, we have deposited thick (5 microns) films of molybdenum which have little residual stress or stress anisotropy.

scholarly journals Effect of Different Manufacturing Process Steps on the Final Residual Stress Depth Profile along the Process Chain of Autofrettaged Thick-Walled-Cylinders

2014 ◽  
Vol 996 ◽  
pp. 676-681 ◽  
Author(s):  
Horst Brünnet ◽  
Michael Hofmann ◽  
Nataliya Lyubenova ◽  
Dirk Bähre
Keyword(s):  
Residual Stress ◽  
Depth Profile ◽  
Manufacturing Process ◽  
Compressive Residual Stress ◽  
Design Tool ◽  
Process Chain ◽  
Technical Process ◽  
Depth Profiles ◽  
The Impact ◽  
Compressive Residual Stresses

Selectively induced compressive residual stress depth profiles are gaining increasing importance as design tool for internally pressurized components. Hydraulic Autofrettage (AF) is a well-known manufacturing process to induce pronounced compressive residual stresses. However, AF does not stand alone in the technical process chain. In this paper, results from neutron diffraction experiments performed on thick-walled cylinders are presented and compared to finite-element simulations with Abaqus/CAE. The impact on the final residual stress depth profile after pre-machining, Autofrettage and post-machining is discussed.

scholarly journals Comparative study: Impact of Ball burnishing and shot peening Process on Aluminium 2024 alloy

2021 ◽  
Vol 23 (08) ◽  
pp. 1768-1775
Author(s):  
◽  
Mahendra Kumara C ◽  
D. Shivalingappa ◽  
Prema. S ◽  
◽  
...  
Keyword(s):  
Residual Stress ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Fluid Pressure ◽  
Ball Burnishing ◽  
Hydraulic Unit ◽  
2024 Alloy ◽  
Burnishing Process ◽  
Aeroengine Components ◽  
Compressive Residual Stresses

Compressive residual stress is the major aspect in the extension of the fatigue life of aeroengine components. In this study, a modified burnishing surface treatment and conventional shot peening process was used was proposed to improve surface integrity characteristics such as surface finish, hardness, and stable, advantageous compressive residual stress in turned Cylindrical Aluminum 2024Specimen. In burnishing process, a rolling rigid spherical HSS ball is pressed across an Aluminum 2024Specimen under definite fluid pressure generated by the hydraulic unit and also shot peening was carried out at a shot velocity of 300 m/s. This research examined the effect of burnishing treatment and shot peening process on beneficial compressive residual stresses.

Microscale Modeling to Study Shot Peening Effects on Aluminum Alloy

2016 ◽  
Author(s):  
H. Bae ◽  
M. Ramulu ◽  
A. Hossain
Keyword(s):  
Residual Stress ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Single Shot ◽  
Impact Model ◽  
Multiple Impacts ◽  
Residual Stress Field ◽  
Multiple Impact ◽  
Microscale Modeling ◽  
Compressive Residual Stresses

Shot peening is a cold working process used to produce a compressive residual stress to modify mechanical properties of metals. It causes impacting a surface with shots with significant force to create plastic deformation. The compressive residual stresses developed by shot peening process helps to avoid the propagation of micro-cracks exist in surface. Shot peening process is often used in aircraft industries to relieve tensile stresses built up in the grinding process, and replace them with beneficial compressive residual stresses. Shot peening has been developed to increase the fatigue strength of metallic parts. Compressive residual stress and surface hardening induced by shot peening process are found beneficial to increase the fatigue life and the resistance to stress corrosion cracking within the metallic component. Even though shot peening has been used for more than 50 years, a review of published papers indicates a lack of studies in numerical modeling. In particular, the effect of complex shot peening process to predict the target material responds to the multiple impacts of shots is not fully revealed. Most studies have investigated the fundamental mechanism and characteristics of fatigue improvement by single shot peening, and have studied the compressive residual stress induced by single normal impact on the surface of the specimen. However, single impact model is appropriate and efficient for sensitivity studies, local plastic effect, and indentation estimation. It is well known that the residual stress by single shot model is not suitable for practical use. The residual stress field from multi impacts is the resultant sum of all the fields by repeated and progressive impacts. It is not feasible to extrapolate results from the single impact model to a practical shot peening process with multiple impacts. Therefore, this research attempts to conduct a microscale modeling to study the shot peening effects of aluminum alloy responds to single and multiple impacts. First, a single shot impact model, representing single shot peening process, has been developed for the estimation of indentations at different velocities. The numerical simulations has been performed with the finite element software code LS-DYNA. The validations of the numerical simulations has been made from experimentally measured surface roughness data. Once the finite element code of single shot peening model is validated, additional numerical models are developed to simulate multiple shot peening process, using multiple impact shots. The multiple impact model are developed for the estimation of the residual stress field.

Investigation on Residual Stress and Flank Wear of Tool Insert in Hard Turning of Chrome Plated EN24 Substrate

2014 ◽  
Vol 4 (2) ◽  
pp. 14-28
Author(s):  
K.N. Mohandas ◽  
C.S. Ramesh ◽  
Eshwara Prasad Koorapati ◽  
N. Balashanmugam
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Compressive Residual Stress ◽  
Hard Turning ◽  
Flank Wear ◽  
Residual Stress Distribution ◽  
A Value ◽  
Cutting Inserts ◽  
Hard Chrome ◽  
Compressive Residual Stresses

In the present investigation the hard chrome plated surfaces were hard turned using PcBN cutting inserts. The results of the experiment showed that the hard turning can be applied for the finish machining of chrome plated surfaces. The influence of hard turning was observed when it was tested for residual stress distribution. The results disclosed that the chrome plating technhique has induced the compressive residual stress of -355.9MPa in the workpieces. These compressive residual stresses increased to a value of -723.3MPa after hard turning the chrome plated surfaces. But with worn out insert a tensile residual stress of 228.1MPa was observed in the workpiece. The results also revealed the variation of flank wear on the tool with different cutting inserts. The conclusions was drawn on the hard turning of hard chrome plated by adopting proper cutting conditions to replace the grinding operation by hard turning operation.

Residual Stress Effects on Crack Growth in Nugget of Al-Li Alloy 2195-T8 Friction Stir Welded Joints

2011 ◽  
Vol 138-139 ◽  
pp. 646-650 ◽  
Author(s):  
Yu E Ma ◽  
Li Ning Wang ◽  
Bao Qi Liu
Keyword(s):  
Residual Stress ◽  
Crack Growth ◽  
Compact Tension ◽  
Parent Material ◽  
Stress Distributions ◽  
Friction Stir ◽  
Stress Effects ◽  
Transverse Welds ◽  
Microstructure Effect ◽  
Compressive Residual Stresses

In this work, Compact-Tension (C(T)) specimens with transverse welds in the sample centre were designed. The residual stress distributions were measured parallel and perpendicular to the weld nugget. Fatigue crack growth (FCG) rates were measured in the lab air. It is shown that compressive residual stresses around notch have significant effect on FCG rates and the effect deceases with crack growing. FCG rate is lower in the nugget than in parent material. Effects of residual stress were studied with crack growing. The lower crack growth rate in nugget is believed to be linked in part to compressive residual stress, but also in part to a microstructure effect present when crack grows in the recrystallized nugget.

scholarly journals The Effect of the Static Load in the UNSM Process on the Corrosion Properties of Alloy 600

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3165 ◽  
Author(s):  
Ki Tae Kim ◽  
Young Sik Kim
Keyword(s):  
Residual Stress ◽  
Compressive Residual Stress ◽  
Static Load ◽  
Impedance Measurement ◽  
Optical Microscope ◽  
Alloy 600 ◽  
Corrosion Properties ◽  
Cyclic Polarization ◽  
Static Loads ◽  
Compressive Residual Stresses

To suppress stress corrosion-cracking, compressive residual stresses, such as shot peening, laser peening, water jet peening, ultrasonic peening, and ultrasonic nanocrystal surface modification (UNSM) are utilized. However, among the numerous techniques, there is little research about the corrosion effect of detailed conditions, such as static load or amplitude in UNSM. A study on UNSM among various techniques of adding compressive residual stress to Alloy 600 was conducted. The focus of this study was on the effect of the static load in UNSM on the corrosion properties of Alloy 600. Microstructure analysis was conducted using an optical microscope (OM), a scanning electron microscope (SEM), and electron backscattering diffraction (EBSD), while compressive residual stress was measured using a nano-indentation technique. A cyclic polarization test and the AC (Alternating Current)-impedance measurement were both used to analyze the corrosion properties. An increase in static load under critical static load enhanced the grain boundary diffusion, consequently strengthened the passive film, and facilitated the surface diffusion, thereby improving the passivation of Alloy 600. However, higher static loads over the critical value can lead to an increase in the friction between the striking tip and the surface, thereby creating an overlapped wave, which reduces the corrosion properties.

The Effect of Cold Expansion at Chamfered Fastener Holes

2007 ◽  
Author(s):  
Jae-Soon Jang ◽  
Dae-Wook Kim ◽  
Myoung-Rae Cho
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Compressive Residual Stress ◽  
Expansion Method ◽  
Stress Distributions ◽  
Equal Distribution ◽  
Cold Expansion ◽  
Hole Expansion ◽  
Hole Position ◽  
Compressive Residual Stresses

Cold expansion method has been widely used to enhance fatigue properties of the aerospace structures with fastener holes. Basically, cold expansion method is that an oversized tapered mandrel goes through the hole and produces compressive residual stress as well as plastic deformation around the hole. One of the problems with the cold hole expansion process is lower compressive residual stress values of the entry hole position than those at other positions of the hole. Often, fatigue cracks are initiated at the entry position of the hole. In this study, applying chamfers on a hole is proposed to increase the residual stresses at the entry position. Finite element analysis (FEA) was conducted to predict residual stress distributions of cold hole expansion processed chamfered holes. FEA results show that the chamfered holes have equal distribution of deep compressive residual stresses around the hole while the holes without chamfers have lower compressive residual stresses at the entry hole position. Effects of chamfer geometries on residual stress distributions are also discussed.

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