Laser Surface Alloying of (Pre-placed) SiC and Ni-SiC Coating on Commercially Pure Titanium

Laser surface alloying is an attractive processing to improve surface hardness, wear and corrosion resistance. In this paper, a continuous wave CO2 laser was used to irradiate commercially pure titanium surface with pre-placed active carbon powders in argon atmosphere. A compact, well-adherent, and crack-free TiC/Ti composite layer was obtained. The microstructure and phase constitution of the alloyed layers were determined and analyzed, and the micro-hardness was measured. The result of X ray diffraction (XRD) analysis shows that the alloyed layers contain TiC and Ti (martensite). The scanning electron microscopy (SEM) observation shows TiC growth morphologies have a well-developed dendrite, cellular dendrite, globular microstructure and cross-petal microstructure. The mechanism of the formation of titanium carbides is discussed. Micro-hardness of the laser surface alloyed layer was improved to 420 Hv as compared to 200 Hv of the as-received commercially pure titanium.

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The Influence of Laser Irradiation Parameters on Tribological Behaviour of Commercially Pure Titanium for Dental Prostheses

Volume 14: Emerging Technologies; Materials: Genetics to Structures; Safety Engineering and Risk Analysis ◽

10.1115/imece2016-66524 ◽

2016 ◽

Author(s):

Karibeeran Shanmuga Sundaram ◽

Gurusami Kiliyappan ◽

Senthil Kumaran Selvadurai

Keyword(s):

Surface Roughness ◽

Wear Resistance ◽

Pure Titanium ◽

Laser Surface ◽

Commercially Pure Titanium ◽

Laser Shock ◽

Micro Hardness ◽

Dental Prostheses ◽

Commercially Pure ◽

Cp Ti

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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