Strengthening mechanism of Nd: Yag laser shock peening for commercially pure titanium (CP-TI) on surface integrity and residual stresses

Laser shock peening (LSP) is one of the innovative technique that produces a compressive residual stress on the surface of metallic materials, thereby significantly increasing its fatigue life in applications where failure is caused by surface-initiated cracks. The specimens were treated with laser shock waves with different processing parameters, and characterization studies were made on treated specimens. The purpose of the present study was to investigate the influence of Nd:YAG laser on commercially pure titanium (CP-Ti) used in prosthetic dental restorations. The treatment influenced change in microstructure, micro hardness, surface roughness, and wear resistance characteristics. Though CP-Ti is considered as an excellent material for dental applications due to its outstanding biocompatibility, it is not suitable when high mastication forces are applied. In the present study, pulsed Nd:YAG laser surface treatment technique was adopted to improve the wear resistance of CP-Ti. The wear test pin specimens of CP-Ti were investment cast with centrifugal titanium casting machine. The wear properties of specimens were evaluated after LSP on a “pin-on-disc” wear testing tribometer, as per ASTM G99-05 standards. The results of the wear experiment showed that the treated laser surface has higher wear resistance, micro hardness, and surface roughness compared to as-cast samples. The improvement of wear resistance may be attributed due to grain refinement imparted by LSP processes. The microstructure, wear surfaces, wear debris, and morphology of the specimen were analyzed by using optical electron microscope, scanning electron microscope, and X-ray diffraction (XRD). The data were compared using ANOVA and post-hoc Tukey tests. The characteristic change resulted in increase in wear resistance and decrease in wear rate. Hence, it is evident that the more reliable and removable partial denture metal frameworks for dental prostheses may find its applications.

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Study of Residual Stresses Introduced by Laser Shock Peening in Wide Chord Fan Blades by Neutron and Synchrotron Diffraction

Journal of Neutron Research ◽

10.1080/10238160410001734694 ◽

2004 ◽

Vol 12 (1-3) ◽

pp. 207-211 ◽

Cited By ~ 3

Author(s):

A. King ◽

A.D. Evans ◽

M. Preuss ◽

P.J. Withers ◽

C. Woodward

Keyword(s):

Residual Stresses ◽

Laser Shock Peening ◽

Laser Shock ◽

Synchrotron Diffraction ◽

Shock Peening

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Thermomechanical Response of Commercially Pure Titanium under Large Plastic Deformation at High Strain Rates

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.548.174 ◽

2012 ◽

Vol 548 ◽

pp. 174-178 ◽

Cited By ~ 1

Author(s):

Chong Yang Gao ◽

Wei Ran Lu

Keyword(s):

Pure Titanium ◽

Optimal Solution ◽

Optimization Method ◽

Strain Rates ◽

Commercially Pure Titanium ◽

Thermomechanical Response ◽

Commercially Pure ◽

Different Temperatures ◽

Cp Ti ◽

Constitutive Parameters

By using a dislocation-based plastic constitutive model for hcp metals developed by us recently, the dynamic thermomechanical response of an important industrial material, commercially pure titanium (CP-Ti), was described at different temperatures and strain rates. The constitutive parameters of the material are determined by an efficient optimization method for a globally optimal solution. The model can well predict the dynamic response of CP-Ti by the comparison with experimental data and the Nemat-Nasser-Guo model.

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Dynamic Material Response of Aluminum Single Crystal Under Microscale Laser Shock Peening

Journal of Manufacturing Science and Engineering ◽

10.1115/1.3106034 ◽

2009 ◽

Vol 131 (3) ◽

Cited By ~ 7

Author(s):

Sinisa Vukelic ◽

Youneng Wang ◽

Jeffrey W. Kysar ◽

Y. Lawrence Yao

Keyword(s):

Residual Stresses ◽

Single Crystals ◽

Electron Backscatter Diffraction ◽

Target Material ◽

Laser Shock Peening ◽

Laser Shock ◽

Laser Target ◽

Aluminum Single Crystal ◽

Anisotropic Mechanical Properties ◽

Shock Peening

The process of laser shock peening induces compressive residual stresses in a material to improve material fatigue life. For micron sized laser beams, the size of the laser-target interaction zone is of the same order of magnitude as the target material grains, and thus the target material must be considered as being anisotropic and inhomogeneous. Single crystals are chosen to study the effects of the anisotropic mechanical properties. It is also of interest to investigate the response of symmetric and asymmetric slip systems with respect to the shocked surface. In the present study, numerical and experimental aspects of laser shock peening on two different crystal surfaces (110) and (11¯4) of aluminum single crystals are studied. Lattice rotations on the top surface and cross section are measured using electron backscatter diffraction, while residual stress is characterized using X-ray microdiffraction. A numerical model has been developed that takes into account anisotropy as well as inertial terms to predict the size and nature of the deformation and residual stresses. Obtained results were compared with the experimental finding for validation purpose.

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The influence of mold temperature on the fit of cast crowns with commercially pure titanium

Brazilian Oral Research ◽

10.1590/s1806-83242005000200012 ◽

2005 ◽

Vol 19 (2) ◽

pp. 139-143 ◽

Cited By ~ 6

Author(s):

Wagner Sotero Fragoso ◽

Guilherme Elias Pessanha Henriques ◽

Edwin Fernando Ruiz Contreras ◽

Marcelo Ferraz Mesquita

Keyword(s):

Pure Titanium ◽

Mold Temperature ◽

Commercially Pure Titanium ◽

Mechanical Grinding ◽

Marginal Fit ◽

Commercially Pure ◽

Cp Ti

Commercially pure titanium (CP Ti) has been widely applied to fabricate cast devices because of its favorable properties. However, the mold temperature recommended for the manufacture of casts has been considered relatively low, causing inadequate castability and poor marginal fit of cast crowns. This study evaluated and compared the influence of mold temperature (430°C - as control, 550°C, 670°C) on the marginal discrepancies of cast CP Ti crowns. Eight bovine teeth were prepared on a mechanical grinding device and impressions were used to duplicate each tooth and produce eight master dies. Twenty-four crowns were fabricated using CP Ti in three different groups of mold temperature (n = 8): 430°C (as control), 550°C and 670°C. The gap between the crown and the bovine tooth was measured at 50 X magnification with a traveling microscope. The marginal fit values of the cast CP Ti crowns were submitted to the Kruskal-Wallis test (p = 0.03). The 550°C group (95.0 µm) showed significantly better marginal fit than the crowns of the 430°C group (203.4 µm) and 670°C group (213.8 µm). Better marginal fit for cast CP Ti crowns was observed with the mold temperature of 550°C, differing from the 430°C recommended by the manufacturer.

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Pack Cementation Treatment of Titanium Using Tetracalcium Phosphate Powder for Biomedical Applications

Materials Science Forum ◽

10.4028/www.scientific.net/msf.654-656.2172 ◽

2010 ◽

Vol 654-656 ◽

pp. 2172-2175

Author(s):

Kyosuke Ueda ◽

Hajime Suto ◽

Kaori Nakaie ◽

Takayuki Narushima

Keyword(s):

Reaction Layer ◽

Biomedical Applications ◽

Pure Titanium ◽

Pack Cementation ◽

Apatite Formation ◽

Commercially Pure Titanium ◽

Tetracalcium Phosphate ◽

Phosphate Powder ◽

Commercially Pure ◽

Cp Ti

The surface modification of commercially pure titanium (CP Ti) by pack cementation treatment at 973 K using tetracalcium phosphate (Ca4(PO4)2O, TTCP) slurry was investigated. An HAp phase and a CaTiO3 phase were observed on the reaction layer of the CP Ti substrate after pack cementation treatment at 973 K for 86.4 ks. TTCP powder decomposed to HAp and CaO, and CaO reacted with TiO2 to form CaTiO3. The reaction layer on the CP Ti substrate consisted of inner and outer layers and the particles were in the outer reaction layer. The pores observed on the reaction layer were formed by the detachment of particles from the outer layer. The bonding strength of the reaction layer was 68.1 MPa. Apatite completely covered the surface of the pack-cementation-treated CP Ti after immersion in Kokubo solution for 21.6 ks; such rapid apatite formation suggests that pack cementation treatment improves the biocompatibility of titanium.

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