Effect Of Surface Finish Research Articles

Effect of Surface Finish and Temperature on Low Cycle Fatigue Behavior of GRCop‐42

Effect of Surface Finish and Temperature on Low Cycle Fatigue Behavior of GRCop‐42

Friction and Wear Behavior of 3D-Printed Inconel 718 Alloy under Dry Sliding Conditions

Tailor-made materials used for advanced applications are nowadays of great research interest in various industrial and technological fields, ranging from aerospace and automotive applications to consumer goods and biomedical components. In the present research, Inconel 718 superalloy specimens were fabricated by the selective laser melting (SLM) technique. Structural characterization of the 3D-printed samples showed that they consisted of γ solid solution along with spherical carbide particles. To explore the applicability of these materials in abrasive tribological applications, reciprocating sliding tests were performed under dry conditions versus an Al2O3 counter-body. A 3D representation (triboscopy) of the tangential force during each sliding cycle was carried out in order to obtain better insight on the evolution of friction and to visualize localized tribological phenomena. Quantification of wear was performed with confocal microscopy and the wear mechanisms were analyzed with SEM and EDS techniques. Furthermore, the effect of surface finishing (as-printed and polished) on friction and wear were also investigated, and a comparison with other industrial materials is also included to evaluate the applicability of these alloys. The results indicated that surface finishing had an effect on friction during the run-in stage, whereas in steady-state conditions, no significant differences were observed between the as-printed and polished specimens. In all cases, the main wear mechanisms observed were a mixture of two-body and three-body abrasion, along with oxidative wear (indicated by the formation of an oxide-based tribo-layer).

Compressive failure and fragmentation of fused silica glass under quasi-static loading

This paper investigates the failure and post-failure fragmentation processes of fused silica glass cylinders under quasi-static compression, addressing the effects of surface finish on apparent strength. The compressive strengths of cylinders with side-polished sides under dry friction conditions (PSG-D) or lubricated conditions (PSG-L) were 2.52 GPa and 2.32 GPa, respectively. In situ observations showed that these specimens fractured from either the top or bottom contact surfaces, and that friction between the specimen and the loading anvil delayed the development of surface cracks. The unpolished rough side specimens (RSG-D) under dry friction conditions failed at a much lower level of 1.54 GPa, initiated by defects in the side surfaces. Specimens "explosively" fragmented upon failure. The propagation speed of the failure front ranged from 1800 to 2800 m/s. The average sizes and distributions of the fragments were determined through statistical analysis, with results showing reasonably close agreement with theoretical estimations.

"Effect of different Tooth Surface Finish on Marginal Adaptation of Laminate Veneers”-an In Vitro Study

"Effect of different Tooth Surface Finish on Marginal Adaptation of Laminate Veneers”-an In Vitro Study

Color stability of precolored and extrinsically colored monolithic multilayered polychromatic zirconia: Effects of surface finishing and aging.

To explore the impact of zirconia types, coloring methods, and surface finishing on the color stability of monolithic multilayered polychromatic zirconia after artificial aging, including thermocycling and simulated toothbrushing. Eighty square-shaped zirconia samples were divided into 2 types (M3Y-TZP and M6Y-PSZ), further categorized based on coloring methods (precolored and extrinsically colored) and surface finishing techniques (mechanical polishing or glazing). The color stability was assessed using the CIEDE2000 formula. Artificial aging was simulated via thermocycling and toothbrushing. All samples were analyzed with a spectrophotometer to determine the post-aging color changes (ΔE00). The ΔE00 were interpreted and classified using the 50:50% perceptibility threshold (PT) and the 50:50% acceptability threshold (AT). Comparisons between groups for ΔE00 differences were performed using three-way ANOVA, with pairwise comparisons facilitated by Fisher's protected least significant difference test, α = 0.05. The study results indicated significant impacts of zirconia type, coloring method, and surface finishing on color stability. The M6Y groups experienced significantly greater color changes (6.61 ± 1.63) compared to the M3Y groups (3.40 ± 2.24), p < 0.0001. For both types of zirconia, extrinsically colored samples exhibited significantly higher ΔE00 when mechanically polished (p = 0.004). However, surface finishing had no significant effect on ΔE00 in precolored samples of either zirconia material (p = 1.000). The evaluation and categorization of ΔE00 variations indicated that nearly all color changes in the M6Y groups, regardless of being precolored, extrinsically colored, polished, or glazed, were deemed extremely unacceptable (Grade 1). In contrast, the M3Y groups showed more acceptable results, with the majority of color changes classified as moderately unacceptable (Grade 3). The color stability of multilayered polychromatic zirconia is influenced by the type of material, extrinsic coloring, and the chosen surface treatment post-artificial aging. The translucent 6Y-PSZ exhibited lower color stability, especially with only mechanical polishing. For the fabrication of M3Y-TZP and 6Y-PSZ monolithic multilayered polychromatic zirconia restorations, extrinsic coloring should be paired with glazing to maintain color stability. Conversely, in the absence of extrinsic coloring, both glazing and mechanical polishing are effective in preserving color stability.

Influence of surface finishing by grinding on the cavitation erosion resistance of 316L and NiAl-bronze

Improving the mechanical properties of bulk and near-surface materials and alternating the dynamics of cavitating bubbles are two main methods to reduce cavitation erosion damage. Grinding and polishing, as two common surface finishing stages, can alter the cavitation erosion damage on metallic materials by affecting both the bubble dynamics and the mechanical properties of the surface. In this paper, the ultrasonic cavitation erosion resistance of 316L and NiAl-bronze alloys, each with two initial surface conditions of grinding and polishing is investigated, focussing on the material reaction. The mechanisms of material removal are discussed based on surface and subsurface observations to explain the effect of surface finishing on the cavitation erosion damage. After 8.5 h cavitation erosion testing time, a lower erosion mass loss was obtained for both alloys in the ground state as compared to the polished state suggesting that grinding can improve the cavitation erosion resistance of alloys. On the other hand, the polishing process improved the erosion resistance of NiAl-bronze at the early stages of cavitation. This is discussed in light of the two distinct surface characteristics of roughness and hardness, which, in turn, tend to increase and decrease cavitation erosion damage. Planar crystallographic boundaries and intermetallic-matrix interfaces were found to be the most susceptible sites to early erosion damage on the polished 316L and bronze, respectively.

Effects of surface finishes, heat treatments and printing orientations on stress corrosion cracking behavior of laser powder bed fusion 316L stainless steel in high-temperature water

Stress corrosion cracking (SCC) of laser powder bed fusion 316 L stainless steel in oxygenated high-temperature water environments with chloride addition at 288 °C was studied. The influences of surface finishes (as-built, mechanically polished, Hirtisation® and shot peened), heat treatments (solution annealing at 1066 and 1150 °C and hot isostatic pressing) and the printing orientations on SCC were evaluated. Hirtisation resulted in a lower SCC susceptibility than as-built or polished surface while shot peening showed the lowest apparent SCC resistance. A high annealing temperature decreases SCC resistance. The effect of printing orientation is material and environment dependent.

Investigation on high cycle fatigue performance of additively manufactured Alloys: Synergistic effects of surface finishing and Post-Heat treatment

The high-cycle fatigue (HCF) behavior of additively manufactured (AM) materials in structural applications remains insufficiently explored when contrasted with conventionally fabricated alloys. Addressing this research gap, we systematically investigate the potential to enhance HCF performance in AM alloys through a strategic interplay of surface finishing and post-heat treatment design. Concentrating on laser powder bed fusion, we evaluate surface roughness and post-heat treatment effects on HCF life across a300to1000 MPa stress range. Findings show that, at700to1000 MPa, surface finishing significantly extends HCF life by mitigating crack initiation. Paradoxically, at300to700 MPa, it shortens HCF life due to induced local residual stress on the sample surface. Additionally, post-aging finishing moderately enhances HCF life compared to pre-aging. This underscores the crucial role of sequence in surface finishing and heat treatment, emphasizing their collective impact on fatigue properties. Our study advances the understanding of post-processing factors influencing AM alloy fatigue properties, providing valuable insights for enhancing mechanical performance.

Translucency and Color Difference of Monolithic Zirconia Restorations: The Effect of Surface Finishing on Background Color

Aim: This study evaluates the effect of different surface finishing procedures on the color and translucency values of monolithic zirconia materials on three different colored composite backgrounds. Materials and Methods: Sixty monolithic zirconia blocks of three different translucency levels were prepared in vitro using computer-aided design/computer-aided manufacturing (CAD/CAM) systems. The correlation between repeat measurements was 0.5, resulting in a sample size of nine samples per group to detect a medium effect size, f = 0.25. Half of the zirconia blocks in each group were subjected to glazing, while the other half were polished ( n = 10). Composite blocks of three different colors were prepared to simulate dental substrates, and the zirconia specimens were placed on these composite backgrounds. The color parameters of the specimens were measured using a spectrophotometer on gray, black, and white backgrounds. Three-way repeated measure ANOVA was used to assess the interaction between the three independent variables (zirconia brand, surface finishing technique, and background color) and the effects of each tested variable on the changes in color and translucency. Results: The surface finishing techniques had a significant effect on the color and translucency of the monolithic zirconia materials. Glazing resulted in higher color differences and lower translucency values compared to polishing. For backgrounds of the same color, no significant differences were detected between the glazed zirconia groups for the same condition ( p &gt; .016). Conclusion: Overall, the study demonstrated the importance of selecting the appropriate surface finishing technique and translucency property of the monolithic zirconia materials to obtain the optimal esthetic results in dental restorations.

The effects of stress ultrasonic rolling on the surface integrity and fatigue properties of TiB2/7050 Al composite

In the present work, a new surface mechanical strengthening (SMS) technique named stress ultrasonic rolling (SUR), which is ultrasonic rolling (UR) assisted with a uniaxial tensile elastic stress field, was reported and successfully conducted on 5 % wt TiB2/7050Al composite. Based on the experimental analysis and numerical simulation, the effects of SUR on surface integrity and fatigue performance of the composite were comprehensively investigated. Compared with ordinary UR, SUR further enhanced the fatigue strength at 106 cycles of the composite by 5 % and prolonged the fatigue life of the composite under the stress level of 532.8 MPa by 1.8 to 3.3 times, which are attributed to the comprehensive effect of excellent surface finish, larger and deeper compressive residual stress (RSc) layer, dispersed TiB2 particles distribution in the surface, and superficial nanocrystalline structures. Besides, the assistance of uniaxial tensile elastic stress field did not increase the amount of surface plastic deformation, which indicates the RSc generated by SUR should have similar mechanical and thermal stability to that produced by ordinary UR treatment.

Biodegradation performance of ball burnished magnesium alloy in stimulated body fluids for bioresorbable implant applications

Magnesium alloys are found to be potential bioresorbable materials. However, the application range of these alloys as bioresorbable materials has been limited due to rapid degradation in physiological fluids. The current study deals with the enhancement of degradation behavior of Mg Ze41A alloy in SBF solution by ball burnishing. Further, the influence of burnishing parameters on biodegradation rate has been investigated by Tafel plots, polarization resistance, electrochemical impedance spectroscopy and surface morphology analysis of degraded samples. Additionally, the biodegradation rate has been estimated by ANFIS modeling. The biodegradation rate of Mg Ze41A has been reduced from 1.106 mm/yr to 0.367 mm/yr with an improvement of 68.82% at optimum burnishing condition of burnishing force 50 N, burnishing speed 1400 RPM, burnishing feed 125 mm/min and 2 passes. ANOVA analysis has revealed that burnishing force and feed have contributed the most for the enhancement. The shift in degradation potential towards noble direction and reduction in degradation current density in potentiodynamic polarization curves and the highest charge transfer resistance in electrochemical impedance spectroscopy of the burnished samples are observed for burnished samples. The results reveal that ball burnishing process is a potential surface modification method in reducing the biodegradation rate of Mg Ze41A alloy. The ball burnishing has resulted in lowest biodegradation rate at a degradation current density of 5.743 μA/cm2 and degradation potential of −1.513 V. The ANFIS model developed with 81 fuzzy rules and triangular membership function estimated the biodegradation rate with an accuracy of 95.03%. The decrease in biodegradation rate of ball burnished magnesium substrate in SBF is essentially due to cumulative effect of compressive residual stress, microhardness, surface finish, work hardening and grain refinement.

Electromigration of Power Devices Part 2: Power Device in Applications in Controlled Environment

In the power semiconductor industry, there is a continuous development toward a higher current capability of devices while device’s dimensions shrink. Although higher current is preferred, the reliability risk of the electromigration (EM) remains challenging. In the present study, a special EM test vehicle is used to investigate the pure EM behavior of power device, following our previous work. The selection of the test condition is discussed in detail, which is defined based on the temperature and current profiles of the device in the actual application, focusing on the applications of the power devices in a controlled environment, i.e., data centers or telecommunication servers. The current and temperature profiles of the device are discussed based on the device’s maximum power dissipation and its respective thermal design. The results show that the different combinations of currents and temperatures can lead to different ratios of acceleration factor between the temperature and the current. Consequently, an inappropriate selection of the testing condition can result in the over-domination of temperature over the current, leading to wrong conclusions. The effects of the PCB surface finish (both Ni and Sn plating) as well as different electron flow directions on the EM were studied. It is concluded that the maximum current that can be applied to a power device in the application within a controlled environment is rather limited by the cooling capability of the system than the EM induced device failure.

The effect of surface finish and post-processing on mechanical properties of 17-4 PH stainless steel produced by the atomic diffusion additive manufacturing process (ADAM)

This study investigates the influence of surface finish and post-processing conditions on the mechanical properties of 17-4 PH stainless steel (SS) produced using the atomic diffusion additive manufacturing process (ADAM). Diverse sample orientations, including horizontal (0°), 30°, 60°, and vertical (90°), were examined, with selected samples undergoing post-processing through machining, polishing, and heat treatment. Tensile strength testing, surface roughness measurement, and hardness measurement were conducted to assess the effect of surface finish conditions and post-processing on mechanical properties. The results reveal significant variations in the tensile strength of the samples based on the build orientation (183.5 to 1034.5 MPa), and subsequent machining. Notably, post-built machining is found to enhance both the absolute ultimate tensile strength (UTS) and the isotropy of the material. Further improvements are attainable through heat treatment. A microstructure analysis, in conjunction with tensile testing outcomes, demonstrates the potential for refining the properties of ADAM-printed samples through suitable machining, heat treatment, and geometry modifications. This study identifies avenues for ongoing process development and outlines possibilities for enhancing mechanical properties of additive manufactured parts, particularly through ADAM process.

Effect of surface finish and resin cement on the bond strength to CAD-CAM ceramics for interim resin-bonded prostheses

Statement of problemResin-bonded prostheses, including interim resin-bonded prostheses, are effective in preserving tooth structure compared with other types of fixed dental prostheses for the replacement of missing teeth. However, loss of retention remains a notable concern with these types of prostheses. PurposeThe purpose of this in vitro study was to investigate the influence of glass-ceramic type, resin type, and surface finish on the shear bond strength (SBS) to the CAD-CAM ceramics used to fabricate interim resin-bonded prostheses. Material and methodsEighty 10×2-mm glass-ceramic disks were fabricated by using a diamond saw (IsoMet 1000), 40 from feldspathic porcelain blocks (Vita Mark II) and 40 from lithium disilicate blocks (IPS e.max CAD). Half of the specimens in each group were left with a dull or matte surface finish after cutting, while the other half were glazed with an add-on glaze (VitaAkzento Plus Glaze Spray and IPS e.max CAD Glaze Spray, respectively). The disks were mounted in acrylic resin, and each group was subdivided into 2, with 1 receiving a photopolymerized resin cement (RelyX Veneer) and the other receiving a flowable composite resin (Filtek Supreme Ultimate Flow) to form 2.38×2-mm cylinders. SBS was determined using a universal testing machine (Instron 4411) in accordance with the International Organization for Standardization (ISO) 29022:2013 standard, and failure modes were analyzed by using a stereomicroscope with ×40 magnification. The data were analyzed with a 3-way analysis of variance and Tukey post hoc analysis. The chi-squared test was used to analyze the failure mode (α=.05 for all tests). ResultsCeramic type, resin type, and surface finish significantly impacted SBS (P<.001, P=.003, P<.001, respectively). Lithium disilicate showed higher SBS than feldspathic porcelain, and flowable composite resin exhibited higher SBS than resin cement. Glazed surfaces displayed lower SBS compared with the dull or matte surfaces. The combinations among the 3 materials also impacted SBS (P=.03). In addition, the combinations between ceramic type and surface finish affected SBS (P<.001), regardless of resin cement type. No other combinations affected the SBS (P>.05). The mode of failure was different among the groups (P<.001). In comparison with all other groups, cohesive failures were most prevalent in feldspathic porcelain with a dull or matte surface finish, regardless of the resin type used. ConclusionsThe SBS to glass-ceramics was influenced by ceramic material, resin cement type, and surface finish. Flowable composite resin showed higher SBS than resin cement. A dull or matte surface finish exhibited greater bond strength than a glazed surface. Lithium disilicate had higher SBS than feldspathic porcelain.

Cavitation resistance of FeMnCrSi coatings processed by different thermal spray processes

Cavitation-resistant FeMnCrSi coatings were developed in the past years as a cost-effective alternative to Co-containing alloys to increase the lifespan of hydraulic machinery. The effect of different chemical compositions, surface finishing, and post-processing treatments was investigated for various processing techniques, namely: Arc Spraying Process (ASP), High-Velocity Oxy-Fuel (HVOF), High-Velocity Air-Fuel (HVAF), Plasma Transferred Arc (PTA), and Cold Gas Spray (CGS). This works consists of a compilation and review of original and literature results, and discusses the microstructure changes imparted by each type of processing and their impact on the coating properties and cavitation resistance. Low heat input high-velocity processes (HVOF, HVAF, CGS) developed a reduced degree of oxidation and porosity, accounting for a cavitation resistance higher than that of the coatings that ASP processed. In addition, ASP coatings showed reduced cohesive strength, with the oxidized inter-splat interface being a preferential site for crack propagation.

Improving Surface Quality and Fatigue Life of Electron Beam Melted Ti6Al4V by Chemical Machining

Due to the high demand for innovative parts from the aerospace, biomedical, and automotive industries, 3D printing of titanium parts is widely researched. Electron beam melting (EBM) is one of the few additive manufacturing techniques that can quickly generate high density components. However, additive manufacturing techniques based on powder beds are characterized by subpar surface finishing, which also results in poor mechanical performances that are not suitable for industrial standards. Thus, surface finishing post processing is generally needed. Since fatigue behavior is strongly affected by surface quality, this work aims to highlight how chemical machining impacts this type of mechanical response. Rotating fatigue beam testing method has been chosen for the experimental campaign since it intrinsically stresses more the sample surfaces, in this way the effect of surface finishing is highlighted.

Corrosion behavior assessment of an Al-Cu alloy manufactured via laser powder bed fusion

Additively manufactured Aluminum-Copper alloys are attracting interest because of their high tensile strength. Nevertheless, the presence of Cu strongly affects the corrosion performances. In this work, the corrosion behavior of an innovative laser powder bed fusion-processed 2139 alloy was investigated, and its corrosion performances were compared to the well-consolidated AlSi10Mg alloy, as well as the parent wrought alloy. Electrochemical, Kelvin probe microscopy and intergranular corrosion tests were performed. The unique corrosion morphology at melt pool boundaries are presented and discussed alongside with the effect of surface finishing and heat treatments.

Effect of non-standard SnAg surface finishes on properties of solder joints

In this study, the effects of nonstandard near-eutectic SnAg surfaces on the wettability, intermetallic compound growth and mechanical properties of solder joints were investigated. Four types of surface finishes based on near-eutectic SnAg alloys with different compositions and numbers of layers were analyzed. Design/methodology/approachThe effect of surface-finishes SnAg5NiP and SnAg7NiP, which were prepared with and without a Ni-P diffusion barrier, was tested. The Ni-P layer was produced either chemically or electrochemically. The effect of the SnAg surface finish on wettability, formation, and growth of intermetallic compound in the solder joint was analyzed. We further explored the impact of different PCB finishes on the quality of soldered joints. This investigation involved a comparative analysis of the behavior of SnAg finishes in comparison to pure copper, as well as the commonly employed HASL, ENIG, and ImSn finishes. FindingsIt was found that SnAg surface finishes with a Ni-P diffusion barrier are wetted by molten solder faster than surface finishes without a diffusion barrier. The mechanical properties of the joints on both surfaces are comparable to those on ENIG. SnAg that include a chemically created Ni-P diffusion layer is characterized by the formation of more thermally stable ternary intermetallic compounds based on (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4. On the contrary, the electrochemically formed Ni layer supports the increase in the rate of intermetallic compound formation, which affects the properties of the soldered joints. OriginalityNonstandard near-eutectic SnAg finishes, which contains a Ni-P diffusion layer can be used as promising replacement of ENIG or other standard finishes.

Evolution of surface roughness of notched steel details under fatigue loading

A fatigue crack initiates on the surface of the steel members, which can be attributed to the extrusions and intrusions caused by cyclic loading. The surface roughness parameters, including the statistical surface roughness and maximum surface roughness parameters, can characterize the increase in extrusion and intrusion. Six notched specimens were loaded with cyclic loading, and the evolution of the surface roughness parameters was monitored during the test to explore the characteristics of the surface roughness during the fatigue loading procedure in the high-cycle fatigue regime and clarify the effects of the initial surface finish and load ratio on the surface roughness evolution. Based on the test results, it was found that the 3D average surface roughness Sa and 3D root-mean-square surface roughness Sq were preferable for detecting the onset of fatigue cracks compared with the 2D average surface roughness Ra and 2D root-mean-square surface roughness Rq. The 3D maximum valley depth, Sv, was an effective indicator of the fatigue crack initiation location, except for compression-dominant fatigue loading. The evolution patterns of the 3D average surface roughness, Sa, and 3D root-mean-square surface roughness Sq during fatigue loading can be classified into three phases: instant response, damage accumulation, and crack-induced response. In addition, surface polishing is recommended for evaluation using 2D surface roughness parameters. However, it is not mandatory for evaluations using 3D surface roughness parameters. The effects of typical load ratios (0.1, −1, and 10) on the evolution pattern of the 3D statistical surface roughness parameters, especially in the instant response phase, were also investigated.

Understanding the Effects of Surface Finish on Diffusion Bonding of AZ31 Alloys

Methods to optimize the diffusion bonding (DB) process while also creating lap joints were investigated using AZ31, the commercial Mg alloy, focusing primarily on studying the effects of varying conventional process parameters and more importantly, exploring the influence of surface roughness on creating an acceptable strong bond. The results indicate that when contact is made between surface areas of roughness (Ra &gt; 0.2 ㎛) diffusion is facilitated at reduced process parameters of time and temperature. Furthermore, this early bond initiation combined with the optimized DB process parameters results in a stronger bond with strengths increasing by ~ 150% in comparison to the DB samples created with a smooth surface finish. Additionally, less than 20% total overall distortion is observed while preserving a uniform microstructure of consistent grain sizes in the material over the entire joining region compared with the parent material.