Effect of laser surfacing on the microstructure and mechanical properties of ultrasonic welded NiTi joints

2021 ◽  
pp. 1-27
Author(s):  
Sansan Ao ◽  
Chunjie Li ◽  
Wei Zhang ◽  
João Pedro Oliveira ◽  
Zhi Zeng ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Plastic Deformation ◽  
Mechanical Interlocking ◽  
Contact Conditions ◽  
Fracture Characteristics ◽  
Laser Surfacing ◽  
Significant Difference ◽  
Metallic Bond ◽  
Elemental Diffusion ◽  
Metallic Bonding

Abstract In the present work, the effects of laser surfacing aiming at modify the surface roughness on NiTi sheets prior to the application of ultrasonic welding (USW) were investigated. Three different configurations joining original and laser surfaced specimens were performed: original/original (referred as O/O), original/treated (referred as O/T); treated/treated (referred as T/T). The influence of surface roughness on the interface formation, diffusion, and mechanical behavior was investigated. It is observed that when both bonding surfaces becomes rougher (T/T configuration), the joint strength is the highest, followed by both smooth bonding surfaces (O/O configuration), and the strength of the joint is the lowest when only one of the bonding surfaces was roughened (O/T configuration), which is related to the degree of plastic deformation at the joining interface. The main joining mechanism of NiTi to the Al interlayer was a metallic bond caused by shear plastic deformation and formation and growth of micro welds at the joining interfaces. Laser surfacing facilitates the metallic bonding, which is directly reflected in the change of the thickness of the Al interlayer after USW. This also helps to produce mechanical interlocking at the interface, although there is no significant difference in the elemental diffusion. Interfacial failure occurred in all joints tested under different surface contact conditions and exhibited ductile-like fracture characteristics.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

scholarly journals Influence of turning tool wear on the surface integrity and anti-fatigue behavior of Ti1023

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110112
Author(s):  
Li Xun ◽  
Wang Ziming ◽  
Yang Shenliang ◽  
Guo Zhiyuan ◽  
Zhou Yongxin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Plastic Deformation ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Tool Wear ◽  
Surface Integrity ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Machined Surface ◽  
Deformation Layer

Titanium alloy Ti1023 is a typical difficult-to-cut material. Tool wear is easy to occur in machining Ti1023, which has a significant negative effect on surface integrity. Turning is one of the common methods to machine Ti1023 parts and machined surface integrity has a direct influence on the fatigue life of parts. To control surface integrity and improve anti-fatigue behavior of Ti1023 parts, it has an important significance to study the influence of tool wear on the surface integrity and fatigue life of Ti1023 in turning. Therefore, the effect of tool wear on the surface roughness, microhardness, residual stress, and plastic deformation layer of Ti1023 workpieces by turning and low-cycle fatigue tests were studied. Meanwhile, the influence mechanism of surface integrity on anti-fatigue behavior also was analyzed. The experimental results show that the change of surface roughness caused by worn tools has the most influence on anti-fatigue behavior when the tool wear VB is from 0.05 to 0.25 mm. On the other hand, the plastic deformation layer on the machined surface could properly improve the anti-fatigue behavior of specimens that were proved in the experiments. However, the higher surface roughness and significant surface defects on surface machined utilizing the worn tool with VB = 0.30 mm, which leads the anti-fatigue behavior of specimens to decrease sharply. Therefore, to ensure the anti-fatigue behavior of parts, the value of turning tool wear VB must be rigorously controlled under 0.30 mm during finishing machining of titanium alloy Ti1023.

scholarly journals Bonding and Thermal Cycling Performances of Two (Poly)Aryl–Ether–Ketone (PAEKs) Materials to an Acrylic Denture Base Resin

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 543 ◽  
Author(s):  
Tzu-Yu Peng ◽  
Saiji Shimoe ◽  
Lih-Jyh Fuh ◽  
Chung-Kwei Lin ◽  
Dan-Jae Lin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Thermal Cycling ◽  
Fatigue Testing ◽  
Lower Surface ◽  
Aryl Ether ◽  
Bonding Performance ◽  
Significant Difference ◽  
Aryl Ether Ketone ◽  
Ether Ketone ◽  
Thermal Cycling Fatigue

Poly(aryl–ether–ketone) materials (PAEKs) are gaining interest in everyday dental practices because of their natural properties. This study aims to analyze the bonding performance of PAEKs to a denture acrylic. Testing materials were pretreated by grinding, sandblasting, and priming prior to polymerization with the denture acrylic. The surface morphologies were observed using a scanning electron microscope and the surface roughness was measured using atomic force microscopy. The shear bond strength (SBS) values were determined after 0 and 2500 thermal cycles. The obtained data were analyzed using a paired samples t-test and Tukey’s honestly significant difference (HSD) test (α = 0.05). The surface characteristics of testing materials after different surface pretreatments showed obvious differences. PAEKs showed lower surface roughness values (0.02–0.03 MPa) than Co-Cr (0.16 MPa) and zirconia (0.22 MPa) after priming and sandblasting treatments (p < 0.05). The SBS values of PAEKs (7.60–8.38 MPa) met the clinical requirements suggested by ISO 10477 (5 MPa). Moreover, PAEKs showed significantly lower SBS reductions (p < 0.05) after thermal cycling fatigue testing compared to Co-Cr and zirconia. Bonding performance is essential for denture materials, and our results demonstrated that PAEKs possess good resistance to thermal cycling fatigue, which is an advantage in clinical applications. The results imply that PAEKs are potential alternative materials for the removable of prosthetic frameworks.

Effect of surface sealant on surface roughness and bacterial adhesion of bulk-fill composites

2021 ◽  
pp. 096739112110055
Author(s):  
Gunce Ozan ◽  
Meltem Mert Eren ◽  
Cansu Vatansever ◽  
Ugur Erdemir
Keyword(s):  
Surface Roughness ◽  
Bacterial Adhesion ◽  
Confocal Laser ◽  
High Caries Risk ◽  
Two Samples ◽  
Significant Difference ◽  
Restorative Materials ◽  
Surface Sealants ◽  
Surface Sealant ◽  
Effect Of Surface

Surface sealants are reported to ensure surface smoothness and improve the surface quality of composite restorations. These sealants should also reduce the bacterial adhesion on composite surfaces however, there is not much information regarding their performance on bulk-fill composite materials. The aim of this study was to evaluate the effect of surface sealant application on surface roughness and bacterial adhesion of various restorative materials. Disc-shaped samples were prepared from a compomer, a conventional composite and three bulk-fill composites. Specimens of each group were divided into two groups (n = 9): with/without surface sealant (Biscover LV, [BLV]). Surface roughness values were examined by profilometry and two samples of each group were examined for bacterial adhesion on a confocal laser scanning microscope (CLSM). Bacterial counts were calculated by both broth cultivation and microscopic images. Results were analyzed with one-way ANOVA and Bonferroni/Dunn tests. Following the BLV application, there was a decrease in the surface roughness values of all groups however, only Tetric N-Ceram Bulk and Beautifil-Bulk groups showed significantly smoother surfaces (p < 0.001). There were no significant differences among material groups without BLV application. Evaluating bacterial adhesion after BLV application, conventional composite had the lowest values among all followed by the compomer group. Beautifil-Bulk had significantly the highest bacterial adhesion (p < 0.05), followed by Tetric N-Ceram Bulk group. Without BLV application, there was no significant difference among bacterial adhesion values of groups (p > 0.05). CLSM images showed cell viability in groups. Bulk-fill composites showed higher bacterial adhesion than conventional composite and compomer materials. The surface sealant was found to be highly effective in lowering bacterial adhesion, but not so superior in smoothing the surfaces of restorative materials. So, surface sealants could be used on the restorations of patients with high caries risk.

scholarly journals Effectiveness and safety of a new dental plaque removal device utilizing micro mist spray for removing oral biofilm in vitro

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hiroki Hihara ◽  
Ryo Tagaino ◽  
Jumpei Washio ◽  
Kittipong Laosuwan ◽  
Dimas Prasetianto Wicaksono ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Mucous Membrane ◽  
Oral Mucosa ◽  
Dental Plaque ◽  
Tooth Surface ◽  
Oral Biofilm ◽  
Plaque Removal ◽  
Treated Area ◽  
Biofilm Removal ◽  
Significant Difference

Abstract Background Removal of oral biofilm from the oral mucosa is essential for preventing risk of respiratory and gastrointestinal infection in elderly people. Currently, no device is available which can remove oral biofilm from oral mucosa effectively and safely. Therefore, the effectiveness and safety of the Micro Scale Mist UNIT (MSM-UNIT), a newly developed dental plaque removal device utilizing high speed sprays of fine water droplets, were evaluated for biofilm removal, including the rate and surface roughness for simulated tooth surface and mucous membrane. Methods Simulated tooth and oral mucosa coated with an artificial biofilm of Streptococcus mutans were used for evaluation of effectiveness, with uncoated substrates as the controls. The MSM-UNIT and a conventional air ablation device were operated under recommended instructions. The effectiveness was evaluated from the rate of removal of the biofilm, and the safety was evaluated from the damage observed by scanning electron microscope and surface roughness. Results The biofilm removal rate of the MSM-UNIT was significantly higher than that of AIRFLOW. Little damage was observed in the area treated by the MSM-UNIT. The surface roughness of the MSM-UNIT treated area on simulated tooth surface and oral mucosa showed no significant difference to the control area. In contrast, cracks and powder were observed in the area treated by AIRFLOW. In particular, the surface roughness of the AIRFLOW treated area for Toughsilon was significantly larger than that of the control. Conclusions The MSM-UNIT could be used safely and effectively for removing biofilm not only on simulated tooth surfaces but also simulated mucous membrane. The MSM-UNIT has no harmful effect on teeth or oral mucosa, and may be used for comprehensive oral care for patients during nursing care and the perioperative period.

scholarly journals Dimensional Accuracy of Dental Models for Three-Unit Prostheses Fabricated by Various 3D Printing Technologies

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1550
Author(s):  
Soo-Yeon Yoo ◽  
Seong-Kyun Kim ◽  
Seong-Joo Heo ◽  
Jai-Young Koak ◽  
Joung-Gyu Kim
Keyword(s):  
Surface Roughness ◽  
Three Dimensional ◽  
Dimensional Accuracy ◽  
3D Analysis ◽  
Digital Light Processing ◽  
Test Models ◽  
Reference File ◽  
Significant Difference ◽  
Jet Printing ◽  
3D Printed

Previous studies on accuracy of three-dimensional (3D) printed model focused on full arch measurements at few points. The aim of this study was to examine the dimensional accuracy of 3D-printed models which were teeth-prepped for three-unit fixed prostheses, especially at margin and proximal contact areas. The prepped dental model was scanned with a desktop scanner. Using this reference file, test models were fabricated by digital light processing (DLP), Multi-Jet printing (MJP), and stereo-lithography apparatus (SLA) techniques. We calculated the accuracy (trueness and precision) of 3D-printed models on 3D planes, and deviations of each measured points at buccolingual and mesiodistal planes. We also analyzed the surface roughness of resin printed models. For overall 3D analysis, MJP showed significantly higher accuracy (trueness) than DLP and SLA techniques; however, there was not any statistically significant difference on precision. For deviations on margins of molar tooth and distance to proximal contact, MJP showed significantly accurate results; however, for a premolar tooth, there was no significant difference between the groups. 3D color maps of printed models showed contraction buccolingually, and surface roughness of the models fabricated by MJP technique was observed as the lowest. The accuracy of the 3D-printed resin models by DLP, MJP, and SLA techniques showed a clinically acceptable range to use as a working model for manufacturing dental prostheses

Investigation on Surface Grinding of Ti-6Al-4V Using Minimum Quantity Lubrication

2012 ◽  
Vol 500 ◽  
pp. 308-313 ◽  
Author(s):  
Guo Qiang Guo ◽  
Zhi Qiang Liu ◽  
Xiao Hu Zheng ◽  
Ming Chen
Keyword(s):  
Surface Roughness ◽  
Plastic Deformation ◽  
Surface Morphology ◽  
Specific Energy ◽  
Minimum Quantity Lubrication ◽  
Grinding Force ◽  
Dry Grinding ◽  
Surface Damages ◽  
Side Flow ◽  
Mql System

This paper investigates the effects of MQL system on the grinding performance of Ti-6Al-4V using SiC abrasive, the evaluation of the performance consisted of analyzing the grinding force, surface roughness and surface morphology. The experiment result indicated that the favorable lubricating effect of MQL oil makes it has the lowest value of grinding force, specific energy and force raito. MQL has better surface finish than dry grinding and fluid grinding has the lowest value of surface roughness under different grinding depth. Surface damages such as: side flow, plastic deformation, redeposition are present in dry and fluid grinding. As grinding depth increased, the damages become much more severe. But in MQL condition, it gives better surface integrity than dry and fluid grinding.

The Effect of Bleach Liquid and Household Cleaner on Surface Hardness and Roughness of Acrylic Base of Orthodontic Appliances

2021 ◽  
Author(s):  
Saeed Noorollahian ◽  
Farinaz Shirban ◽  
Vahid Mojiri
Keyword(s):  
Surface Roughness ◽  
Hydrochloric Acid ◽  
Sodium Hypochlorite ◽  
Surface Hardness ◽  
Acrylic Resin ◽  
Liquid Sodium ◽  
P Value ◽  
Orthodontic Appliances ◽  
Acrylic Resins ◽  
Significant Difference

Introduction: The daily use of orthodontic removable plates can interfere with the self-cleansing function of the mouth. Although various techniques have been proposed for cleaning removable orthodontic appliances, there is no consensus on the use of a safe method that preserves the physical properties of the appliance. This study aimed to investigate the effect of using hydrochloric acid (10%, for removal of mineral deposits) and sodium hypochlorite (5.25%, to remove organic matter and discolorations) on surface hardness and roughness of self-cure orthodontic acrylic resins. Materials & Methods: This cross-sectional laboratory study was conducted in the fall of 2017 at Isfahan University of Medical science and Isfahan University of Technology. In this study two orthodontic acrylic resins (Orthocryl® and Acropars®) were used. Eighty samples (12×10×3 mm) from each one were fabricated and divided into four groups (n = 20). Group 1: 15 minutes immersion in household cleaner liquid (Hydrochloric acid, 10%) followed by15 minutes immersion in household bleach liquid (Sodium Hypochlorite, 5.25%). In group 2, immersions were repeated just like group two times and in group 3, were done three times. Group 4 was as control and had no immersion. The surface hardness and roughness of samples were measured. Data were analyzed with Two Way ANOVA and the significance level was set at 0.05. Results: The number of immersion procedures did not significantly affect the surface hardness (p value = 0.958) and surface roughness (p value = 0.657) in the different study groups. There was no significant difference in the surface hardness between the two acrylic resin brands (p value = 0.077); however, Acropars acrylic resin samples exhibited significantly higher surface roughness compared to the Orthocryl acrylic resin samples(p value < 0.001). Conclusion: 15 minutes of immersion in 10% HCl, followed by 15 minutes of immersion in 5.25% NaOCl and repetition of the procedure three times did not significantly affect the surface hardness and roughness of self-cured acrylic resins.

Evaluation of Polishing Systems for CAD/CAM Polymer-Infiltrated Ceramic-Network Restorations

2021 ◽  
Author(s):  
CA Jurado ◽  
A Tsujimoto ◽  
H Watanabe ◽  
NG Fischer ◽  
JA Hasslen ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Computer Aided Design ◽  
Dental Students ◽  
Faculty Members ◽  
Dental School ◽  
Control Group ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
A Company

SUMMARY Objective: The purpose of this study was to evaluate the effectiveness of five different polishing systems on a computer-aided design and computer-aided manufacturing (CAD/CAM) polymer-infiltrated ceramic-network restoration with nanoscale assessment using atomic force microscopy (AFM) and visual assessment performed by dental school senior students and faculty members. Method: Forty-eight full coverage crowns were milled out of polymer-infiltrated ceramic-network CAD/CAM blocks (Vita Enamic) for polishing with one company proprietary, two ceramic and two composite polishing systems. The prepared crowns were divided into six groups: (1) no polishing (control); (2) polishing with Vita Enamic Polishing Kit (VEna); (3) polishing with Shofu Porcelain Laminate Polishing Kit (SCer); (4) polishing with Brasseler Dialite Feather lite All- Ceramic Adjusting & Polishing System (BCer); (5) polishing with Shofu Composite Polishing Kit (SCom); and (6) polishing with Brasseler Composite Polishing Kit (BCom). The polished crown surface topography was observed, and surface roughness and area were measured with AFM. In addition, polished crowns were visually assessed by 15 senior dental students and 15 dental school faculty members. Results: All polishing treatments significantly reduced the surface roughness and area of the crown compared with the control. SCom and BCom showed significantly higher surface area than VEna, and the SCer and BCer groups were intermediate, showing no significant difference from either VEna or SCom and BCom. There were no significant differences in surface roughness between any of the systems. Dental students and faculty members classified the groups polished with VEna, SCer, and BCer groups as clinically acceptable, and they selected BCer group as the best polished restorations and the control group as the least polished restorations. Conclusions: Ceramic and composite polishing systems produced similar polishing results as that observed using a company proprietary polishing system. However, effectiveness for polishing using a company proprietary and ceramic polishing system tends to be higher than composite polishing systems.

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