Type Ti Research Articles

Effect of ωiso and α precipitation during aging on tensile properties and impact toughness of a metastable β type Ti alloy

Effect of ωiso and α precipitation during aging on tensile properties and impact toughness of a metastable β type Ti alloy

Revealing the displacive and diffusional phase transformations in a low-modulus Ti-12Nb alloy

Non-toxic and biocompatible Ti alloys with low modulus are promising biomaterials for implants. Except from the intensely studied metastable β Ti-Nb-based alloys, the α′-type Ti alloys could also present low modulus. But due to the low β stability, the microstructures of these α′ Ti alloys are sensitive to the heat-treatments especially to the cooling rates, which could lead to very different deformation mechanisms and mechanical properties. Thus, the phase transformations and the ‘microstructure–mechanical property’ correlation in the α′ Ti alloys need to be established. In this study, a novel Ti-12Nb wt% alloy was prepared and cooled from the β region temperature to obtain the water-quenched (WQ), air-cooled (AC), and furnace-cooled (FC) samples. Systematic investigations revealed the displacive β → α′ martensitic transformation in the WQ and diffusional β → β + α transformation in the AC and FC samples, in which the α′/α show evident variant selections. The inter-variant orientation relationships (ORs) among the α′/α variants and their ORs with the retained β phase, were found to be agree well with the classical Burgers OR. The high-resolution transmission electron microscope (HRTEM) studies show coherent α′/α′ interfaces in the WQ samples and α/β phase boundaries in the AC and FC samples, the abnormal β nanodomains inside the α′ martensites in WQ samples and the ω nanoparticles in the β phase of AC and FC samples were also presented. The tensile tests show increasing Young's modulus of 61.8 GPa, 77.1 GPa and 108.6GPa in the WQ, AC and FC samples, respectively. The difference in the modulus of these samples was explained by the Nb dependency of Young's modulus in the Ti-Nb alloy. The correlations between the microstructures, deformation mechanisms and mechanical properties were established. The {101¯1}α′ and {101¯2}α′ deformation twins inside the α′ martensites are believed to contribute to the good plasticity in the WQ samples, while the fine α + β structures and severely piled-up dislocations should account for the high yield strength and the poor plasticity in the AC samples. The abundant mobile dislocations in the α bands and deformation-induced ω needles in the surrounding β phase led to the best plasticity in the FC samples among all Ti-12Nb samples. This study systematically studied the displacive and diffusional transformations and the plastic deformation in a Ti-12Nb alloy, the results might pave the way for designing low-modulus biomedical α′ Ti alloy with low content of β stabilizing elements and provide insights into tailoring of the phase transformations and mechanical properties in these Ti alloys.

Development of a high-pressure 700 bar metal hydride hydrogen compressor

HySA Systems and TF Design have recently developed a single-stage prototype high-pressure metal hydride hydrogen compressor (MHHC) which is able to compress hydrogen from 100 to >700 bar at the working temperatures from 20 to 150 °C, with estimated productivity about 1 Nm3/h. The MHHC comprises of two 2 m-long fibre-wound high-pressure MH containers developed by the authors earlier and assembled in two modules operating in a mode of a cyclic lower-pressure H2 absorption (on cooling) and high-pressure H2 desorption (on heating). The containers operate using a self-developed multicomponent C14 Laves type Ti–based AB2 intermetallic alloy. The article considers phase-structural and hydrogen sorption properties of the utilized metal hydride material, hydrogen compression performances of the metal hydride container, as well as layout and the expected performance characteristics of the compressor assembly.

Exploring Ti active sites in Ziegler-Natta catalysts through realistic-scale computer simulations with universal neural network potential

We investigate the interaction dynamics between TiCl4 molecules and a MgCl2 (110) cluster to understand the complexities of Ziegler-Natta catalysts through molecular dynamics simulations. Our study reveals significant distortion of Mg atoms at the edge of cluster, influencing TiCl4 adsorption behavior, cluster stability, and reactivity. Various TiCl4 configurations on the MgCl2 surface, such as octahedral and bridging forms, illustrate the versatility of surface in accommodating different molecular arrangements, affecting catalytic performance. We explore diverse adsorption sites influenced by surface topology and electronic properties, revealing a range of adsorption energies from 15.7 to 29.2 kcal/mol. This indicates a complex interplay of molecular forces, significantly impacting catalytic efficiency at distorted sites. Nudged Elastic Band calculations reveal varied activation energies for ethylene insertion, suggesting faster reaction rates at certain sites and highlighting highly favorable dynamics at Corradini type Ti active sites. All these findings offer new directions for enhancing catalyst performances.

Carbon-coated TiNb2O7 microspheres with partial nitridation for high-performance lithium storage

TiNb2O7 has been applied to lithium-ion batteries owing to its large capacity and inherent safety, but suffers from its poor rate capability. Here, TiNb2O7 is modified through a combination of crystal-structure modification and conductive-phase coating, and C–NH3–TiNb2O7 with Ti2Nb[Formula: see text]O[Formula: see text]-type TiNb2O7 and Ti[Formula: see text][Formula: see text]Nb[Formula: see text]N/carbon double coatings is successfully synthesized. The unique Ti2Nb[Formula: see text]O[Formula: see text]-type structure of TiNb2O7 owns a large interlayer spacing, leading to fast Li[Formula: see text] diffusivity and remarkable intercalation-pseudocapacitive behavior. The conductive Ti[Formula: see text][Formula: see text]Nb[Formula: see text]N/carbon coatings result in good electrical conduction among the TiNb2O7 microspheres. Consequently, C–NH3–TiNb2O7exhibits excellent rate capability of TiNb2O7 (large capacity percentage of 73.9% at 5C versus 0.5C). Besides the fast electrochemical kinetics, C–NH3–TiNb2O7 further exhibits large reversible capacities (237 mAh g[Formula: see text]at 0.1C and 146 mAh g[Formula: see text]at 5C) and outstanding cyclability (93.1% capacity retention after 500 cycles at 5C). These desirable electrochemical properties fully demonstrate that the C–NH3–TiNb2O7 anode material can be suitable for high-performance Li[Formula: see text]-storage.

A Review on the Properties of β Type Ti Alloys: Microstructure, Mechanical, Corrosion Properties and Production Methods

Biyomedikal malzeme endüstrisi, insanların hayat kalitesini ve buna bağlı aktivitelerini sürdürebilmeleri amacıyla dünya çapında gelişmeye devam etmektedir. Yaşlı nüfus ve refah seviyesinin artış göstermesi biyomedikal malzeme sektörünün hızlı bir şekilde büyümesini sağlayan başlıca sebepler arasındadır. Vücut içerisinde implantasyonun yapılacağı bölgenin özelliklerine göre tercih edilen malzeme grubu değişmektedir. Bu malzemeler arasında metalik biyomalzemeler üstün mekanik özelliklerinden dolayı yüksek kullanım oranına sahiptir. Polimer esaslı, seramik esaslı ve kompozit biyomalzemelerde olduğu gibi metalik biyomalzemelerin de konak canlıda oluşturduğu problemler birçok etkene bağlıdır. Oluşan sorunlara karşı yapılan çalışmalar ve gelişen teknoloji ile birlikte günümüzde yenilikçi çözümler üretilmektedir. Metalik biyomalzemeler sahip oldukları yüksek elastisite modülü ile biyomekanik uyumsuzluğa sebep olurken, içerdikleri alaşım element iyonlarının toksik etki oluşturması sonucunda biyouyumluluğu tehlikeye atmaktadırlar. Bundan dolayı derleme doğrultusunda temelde yaşanan iki probleme karşı geliştirilen, biyouyumluluğu yüksek elementlerle alaşımlanan ve faz yapısı sayesinde düşük elastisite modülüne sahip olan β tipi Ti alaşımlarının özellikleri incelenmiştir. Bununla birlikte, β tipi Ti alaşımlarının üretim yöntemlerinin alaşım üzerindeki etkileri üzerinde durulmuş bu noktada toz metalürjisi teknolojisi ile geliştirilen alaşımların verimliliği araştırılmıştır.

Hydrogen storage properties of AB2 type Ti–Zr–Cr–Mn–Fe based alloys

This investigation explores the solid-state hydrogen storage properties of two series of hydrogen storage alloys: (Ti0.85Zr0.15)xMn0.8CrFe0.2 (x = 1.00∼1.10) and (Ti0.85Zr0.15)1.02MnyCr1.8-yFe0.2 (y = 1.00∼0.40) alloys. These alloys exhibit a single C14-Laves phase structure and demonstrate promising capabilities for solid-state hydrogen storage. The (Ti0.85Zr0.15)xMn0.8CrFe0.2 (x = 1.00∼1.10) alloys display an increased hydrogen absorption capacity and a reduced plateau pressure at higher super-stoichiometric ratios of x. When x = 1.10, the alloy achieves a maximum capacity of 1.86 wt%. The hydrogen storage capacity of the (Ti0.85Zr0.15)1.02MnyCr1.8-yFe0.2 (y = 1.00∼0.40) alloys diminishes as the value of y decreases. Furthermore, the hydrogen absorption plateau pressure and hysteresis factor of the alloys increase with an escalating Mn/Cr ratio. The analysis of cyclic stability reveals that the primary factor contributing to poor cycling stability of the (Ti0.85Zr0.15)1.02Mn0.4Cr1.4Fe0.2 alloy is the compositional decomposition, rather than pulverization or alterations in the phase structure.In summary, this investigation enhances our understanding of the solid-state hydrogen storage properties of these alloys. It establishes a foundation for further research and development in this pivotal field of hydrogen storage.

A detailed analysis of the structural, morphological characteristics and micro-abrasive wear behavior of nitrided layer produced in α (CP–Ti), α+β (Ti–6Al–4V), and β (TNZ33) type Ti alloys

The present work aimed to create a hard surface on a titanium surface via plasma nitriding to improve microhardness and wear properties of the as-cast (α-CP-Ti (CP–Ti), α+β-Ti6Al4V (Ti–Al–4V), and β-Ti-33Nb–33Zr (TNZ-33) samples. For the nitriding process, two temperature conditions (650 °C and 700 °C) were used. The presence of nitrides was evaluated by XRD. The microstructure and chemical composition were studied by electron microscopy and EDS. The roughness was evaluated by confocal microscopy. The microhardness and wear properties were analyzed using the Vickers microhardness and micro-abrasive wear test. Plasma nitriding led to the formation of TiN on CP-Ti, TiN, and Ti2N on Ti–6Al–4V, and TiN and ZrN on TNZ-33 samples. At 700 °C, the TiN increased on CP-Ti, while the Ti2N increased for Ti–6Al–4V and the ZrN increased for TNZ-33. The length of the nitride layer decreased when the temperature increased for CP-Ti and Ti–6Al–4V samples. However, for the TNZ33 alloy, the layer increased from 6.3 to 7.6 μm. The chemical analyses confirmed the presence of nitrogen on the substrate surfaces. After the nitriding process, all materials significantly increased the hardness. The hardness after plasma nitriding can be followed by: CP-Ti > TNZ-33> Ti–6Al–4V (at 650 °C); CP-Ti > Ti–6Al–4V > TNZ-33 (at 700 °C). The wear properties of all samples were improved after plasma nitriding treatment.

Achieving low elastic modulus, excellent work hardening and high corrosion resistance in Ti-6Al-4V-5.6Cu alloy

Biomedical Ti-6Al-4 V-5.6Cu alloys with low elastic modulus, excellent work hardening and outstanding corrosion resistance were achieved by manipulating the fractions of martensite phases made up of α″ and α′. The main cause of the low modulus, great work hardening and high elongation is due to the presence of α″ phase. The martensite reorientation induced plasticity (MRIP) phenomenon, which was infrequently recorded in (α + β) -type Ti alloys, was produced when the α″ converted into twined α′ and caused the reorientation of the remainder α′. The sample solid solution treated at 800 °C exhibited greater corrosion resistance than all other tested alloys due to the dissolution of Ti2Cu phases and the comparable proportion of martensite to primary α (martensite/primary α area ratio is approximately 0.69). The optimized Ti-6Al-4 V-5.6Cu alloy exhibited strong potential for development as a biomedical implant material due to its combination of low elastic modulus (55 GPa), high YS/E ratio (10.25), excellent work hardening performance (Δσ = 848 MPa), and superior corrosion resistance.

Evaluation of Ti/Pt Anode Efficiency and Energy Consumption in Turbidity and Suspended Solids Removal from Paper Industry Wastewater: The Effect of pH and Support Electrolyte Type

In the research, different experimental setups were used to examine the treatment of wastewater from the paper industry using the electrooxidation method, one of the electrochemical treatment methods in the batch system. In the 2000 mL volume jacketed glass reactor utilized for the treatment of wastewater from the paper industry, 4 anode and 4 cathode sieve type plates of 7 cm x 10 cm dimensions were positioned at 0.5 cm intervals, and 1200 mL wastewater was used in the tests. Coated sieve type Ti/Pt electrodes were employed as the anode in the electrooxidation studies, and uncoated sieve type Ti electrodes were used as the cathode. It was determined that the active anodic wet surface area was 1078 cm2 . The removal rates of pollutant parameters such as turbidity and SS (Suspended Solids) in the experiments; the effects of wastewater initial pH value and supporting electrolyte type parameters were investigated. According to the results, the most effective pH value for Ti/Pt anode type at 400 rpm mixing speed was determined to be waste water natural pH (7.5), and 0.50 M NaCl was the most successful supporting electrolyte type. 96.92% Suspended Solids removal efficiency and 95.38% turbidity removal efficiency for Ti/Pt anode were achieved under ideal conditions. In addition, 312.05 kW-hour/kg COD is determined as the energy consumption value.

Microstructure characteristics and superelastic properties of novel Ti–Cr–Sn superelastic alloys

Microstructures, texture, lattice deformation strain, and superelastic properties of four kinds of near β type Ti–Cr–Sn novel superelastic alloys were systematically investigated, i.e., Ti-2.5Cr-8.5Sn, Ti-3.0Cr-7.5Sn, Ti-3.5Cr-7.0Sn, and Ti-4.0Cr-6.5Sn (at.%). All the alloys after the solution-treatment at 1273 K followed by water quenching consisted of equiaxed β single phase grains at room temperature in addition to athermal ω phase particles. Mechanical tests revealed the largest superplastic recovery strains (excluding elastic strain) of 4.0% in Ti-4.0Cr-6.5Sn alloy. This is partially due to the large lattice deformation strain ∼6.32% and its well-developed 112β⟨110⟩β texture component when tensile test exqmined along the rolling direction (RD). Moreover, up to 100 cyclic loading-unloading tensile tests revealed that both Ti-4.0Cr-6.0Sn and Ti-2.5Cr-8.5 Sn alloys maintained almost perfect and large shape recovery strain (including elastic strain) over 4.5% without any additional thermo-mechanical treatment. Besides, the starting stress for inducing martensitic transformation in Ti-4.0Cr-6.5Sn alloy kept higher than 200 MPa during the 100 cycles. Based on these superior superelastic properties, it is concluded that these Ti–Cr–Sn superelastic alloys become practical alternatives to replace Ti–Ni not only for biomedical applications but industrial applications.

High Cycle Fatigue and Very High Cycle Fatigue of Orthorhombic (O + α<sub>2</sub>)-Type Ti–27.5Nb–13Al Alloy with and without B and Fatigue Striation Analysis in Comparison with (α + β)-Type Titanium Alloys

The lightweight and high strength Ti–27.5Al–13Nb intermetallic alloy, based on the orthorhombic Ti2AlNb phase (O phase) and the α2 phase incorporated, was previously developed by the authors. This alloy would seem to have good potential for applications where fatigue behavior is a main concern, such as automobile and aircraft engine parts. The minor addition of boron (B) is known to refine the ingot grain size and thus to improve the subsequent mechanical properties. For these reasons, the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) properties of B-free and 0.1 pct B-modified Ti–27.5Al–13Nb alloy were examined in the present study. HCF tests were performed at room temperature (RT) in tension-tension mode at an R of 0.1 and a frequency of 10 Hz, while VHCF tests were performed using an ultrasonic resonance fatigue test machine at an R of −1 and a frequency of 20 kHz. In both fatigue tests, hourglass-shaped specimens were used. With the addition of 0.1 pct B, the prior B2 grain size of an ingot was reduced drastically, from 600∼1000 µm for the B-free alloy to 100∼250 µm. The 0.1 pct B-modified Ti–27.5Al–13Nb alloy with a duplex microstructure consisting of a globular α2 phase and a lamellar microstructure exhibited superior elongation of 6.1 pct at RT. The HCF curve for this alloy with a duplex microstructure was almost the same as that for a Ti–6Al–4V alloy with a fully lamellar microstructure. Although prolonged fatigue life was previously reported in the HCF region in the 0.1 pct B-modified Ti–6Al–4V alloy, the addition of 0.1 pct B to the Ti–27.5Al–13Nb, Ti–6Al–4V and Ti–4Al–2.5V–1.5Fe alloys had no such effect in the VHCF region. VHCF strength for a lamellar microstructure was ranked in the order of Ti–4Al–2.5V–1.5Fe, Ti–6Al–4V and Ti–27.5Al–13Nb from the highest. Well-defined striations were observed at the propagation stage area of the fatigue fracture surface of B-free Ti–27.5Al–13Nb, and the measured striation spacing kept a constant of 0.29 µm through the propagation distance of 300 µm. The calculation based on this observation showed that the fatigue life spent in the propagation stage was very short and thus almost 100 pct of HCF life was thought to be spent in the fatigue initiation stage. For the B-free Ti–6Al–4V alloy with an equiaxed microstructure, the striation spacing increased from 0.06 µm to 4 µm as the fatigue crack propagated for a distance of 1,000 µm. Calculation based on the striation spacing revealed that, similar to the case with the Ti–27.5Al–13Nb alloy, the fatigue initiation stage consumed almost 100 pct of fatigue life regardless of the B addition.

Influence of sintering parameters on the grain growth and mechanical properties of Ti(C,N)-based cermets prepared via mechanical activation and in-situ carbothermal reduction

Series of new type (Ti,Mo)(C,N)-based cermets sintered at different final sintering temperatures were prepared by the mechanical activation and in-situ carbothermal reduction method in vacuum. The grain growth behavior of the complete solid solution cermets was firstly studied by prolonging the holding time at 1400 °C by using XRD, SEM, and TEM. Results indicated that the thermodynamic three-dimensional equilibrium morphology of the hard-phase particles were {111}-faceted and round-edged octahedron, whose growth mechanism were predominated by the two-dimensional nucleation that controlled by the diffusion of the dissolved alloying elements in the binder along the close-packed direction. The microstructure and mechanical properties of the cermets were also studied. The results indicated that either too low or too high sintering temperature could deteriorate the homogeneity and porosity of the cermets. Only when the sintering temperature was 1400 °C, the optimum TRS, hardness, and fracture toughness of the cermets were 2134±30 MPa, 88.0±0.3 HRA, and 20.1±0.3 MPa·m 1/2 , respectively.

Local structure in high-entropy transition metal diborides

Studies on high-entropy materials often speculate about the effects of lattice distortion and disorder on characteristics such as hardness, thermal expansion, and electronic properties. Notwithstanding the ongoing race to discover new compositions, investigations of the local structure at the atomic level remain sparse at best. Additionally, assessments of the homogeneity of the distribution of metals within the lattice sites are often restricted to techniques such as energy dispersive spectroscopy which might lead to an inaccurate picture of the bulk material. Herein, we report an extensive and systematic study of a class of emerging high-entropy ceramics that uses a combination of high-resolution synchrotron powder diffraction and extended X-ray absorption fine structure analysis. Our data are consistent with a random distribution of atoms with local strain around the d-metals sites, which describes the bulk structure of these materials. Moreover, a linear trend is observed between the average structure and the first-neighbour distances, regardless the number (from 3 to 5) and type (Ti, Zr, Nb, Hf, Ta, Mo, W) of metals that constitute the high-entropy ceramic, which suggests that any description of properties for such materials need to go beyond the simple dichotomy of long-range order and local structure.

Preparation and characterization of novel as-cast Ti-Mo-Nb alloys for biomedical applications

Ti and its alloys are the most used metallic biomaterials devices due to their excellent combination of chemical and mechanical properties, biocompatibility, and non-toxicity to the human body. However, the current alloys available still have several issues, such as cytotoxicity of Al and V and high elastic modulus values, compared to human bone. β-type alloys, compared to α-type and (α + β)-type Ti alloys, have lower elastic modulus and higher mechanical strength. Then, new biomedical β-type alloys are being developed with non-cytotoxic alloying elements, such as Mo and Nb. Therefore, Ti-5Mo-xNb system alloys were prepared by argon arc melting. Chemical composition was evaluated by EDS analysis, and the density measurements were performed by Archimedes' method. The structure and microstructure of the alloys were obtained by X-ray diffraction and optical and scanning electron microscopy. Microhardness values were analyzed, and MTT and crystal violet tests were performed to assess their cytotoxicity. As the Nb concentration increases, the presence of the β-Ti phase also grows, with the Ti-5Mo-30Nb alloy presenting a single β-Ti phase. In contrast, the microhardness of the alloys decreases with the addition of Nb, except the Ti-5Mo-10Nb alloy, which has its microhardness increased probably due to the ω phase precipitation. Biological in-vitro tests showed that the alloys are not cytotoxic.

Facile synthesis of [ONON] type titanium(IV)bis-chelated complexes in alcoholic solvents and evaluation of anti-tumor activity

Novel anti-tumoral diamino-bis-(phenolato) [ONON] type titanium(IV) complexes stabilized by 2,6-dipicolinic acid were synthesis via an efficient protocol using n-propanol as solvent and H2O for isolation. In total 20 [ONON] type and 2 Salan Ti(IV)bis-chelated complexes were synthesized with yields ranging from 68% to 96%. All reactions could reach to completion in 1.5 min at 80 °C either using Ti(OiPr)4 or TiCl4 as starting materials. Most [ONON] type Ti(IV) complexes exhibit selectively enhanced inhibition activity against Hep G2 cells in comparison with Salan Ti(IV) complexes. Among which, the inhibitory activity of 2 t (IC50: 0.15 ± 0.1 μM) against Hep G2 cells is about 80 times enhanced than that of cisplatin (IC50: 12.4 ± 1.2 μM). The [ONON] type Ti(IV) complexes slowly released nontoxic phenolato ligands in presence of large amount of aqueous media, and a fast cellular uptake process was proposed for these Ti(IV) complexes based on metal uptake analysis. Decagram scale synthesis indicates this facile synthetic methodology can be applied to large scale synthesis.

Robust mechanical properties and corrosion resistance of new low-cost hot-forged and aged [formula omitted]-type Ti–14Mn–(x)Zr alloys

Low-cost β-type Ti–14Mn–(x)Zr (x = 0, 3, or 6 wt%) alloys were developed and prepared using single-electrode arc furnace, and the effects of the zirconium (Zr) content and thermomechanical treatment on the phase stability, microstructural evolution, hardness, compressive stress, and corrosion resistance of the alloys were studied. The alloy thickness was reduced by approximately 45% by hot forging at 900 °C and were then water quenched and subsequently aged at 500 or 700 °C for different times. The combination of the proper Zr content, hot forging, and aging improved the alloy hardness, strength, and ductility. The dual (α + β) structure formed in the 6Zr alloy forged and then aged at 700 °C for 60 ks resulted in a high compressive yield stress of 1127 MPa and malleability above 70%. The forged and annealed alloys exhibited superior properties to commercial Ti–6Al–4 V (lower cost, corrosion resistance, and mechanical properties). The study findings elucidate the relationship between the composition and processing properties of low-cost Ti–14Mn–(x)Zr alloys for potential biomedical applications.

Effect of multilayer coatings based on zirconium and titanium on wear resistance of carbide tools during turning of stainless steel

In this article, the influence of coatings of the type (Ti—Zr)N—TiN, TiN—ZrN and ZrN—(Ti—Zr)N—TiN obtained by physical vapor deposition on the wear resistance of T15K6 cemented carbides plates during longitudinal turning blanks from stainless steel 12X18H10T is considered. It has been experimentally established that the presence and composition of the coating on the working surfaces of the tool in all cases contributes to a significant decrease in the wear rate of cemented carbides inserts. According to the research results, the composition ZrN—(Ti—Zr)N—TiN should be considered the best option. During the cutting process, for a tool with this type of coating, the minimum wear along the flank surface and the length of chip contact with the rake surface, as well as the smallest values of the shear angle in the zone of primary plastic deformations, were recorded.

Differences in the effect of surface texturing on the wear loss of β-type Ti–Nb–Ta–Zr and (α+β)-type Ti–6Al–4V ELI alloys in contact with zirconia in physiological saline solution

The effectiveness of dimple surface texturing via picosecond pulsed laser processing for reducing wear loss was investigated using two types of titanium alloys, β-type Ti–29Nb–13Ta-4.6Zr (TNTZ) and α+β-type Ti–6Al–4V ELI (Ti64). The two alloys showed different modes of wear against zirconia. As the sliding distance increased, the wear loss was observed to increase for Ti64, but not necessarily for TNTZ. The wear debris of Ti64 acted as abrasive particles, but that of TNTZ easily adhered to the surface, and the adhered wear debris turned into a hard wear-protective layer. Therefore, the dependence of wear loss on the sliding distance for these two titanium alloys could be attributed to the difference in the roles of wear debris between each titanium alloy and zirconia. Further, depending on this difference in wear mode, the effect of dimple surface texturing on the wear was found to be different in Ti64 and TNTZ. As the dimples can trap the wear debris, they are effective for reducing wear in Ti64 but are detrimental in TNTZ.

Laser retrieval of cemented zirconia single unit implant restoration: A pilot study: Part I - Force values.

To measure the retrieval force required to remove 1.5-mm-thick CAD/CAM zirconia copings cemented on zirconia (Zr) and titanium (Ti) stock implant abutments after a single application of erbium-doped yttrium scandium gallium garnet (Er:YSGG) laser. A total of 60 monolithic Zr copings were cemented on Zr and Ti implant abutments with either a resin-modified glass-ionomer (RelyX Luting Plus Cement, 3M ESPE; Rx) or a zinc oxide eugenol cement (Temp-Bond, Kerr; Tb). These abutment-coping specimens were randomly divided into 12 groups based on laser application (vs control [C]), abutment type (Zr vs Ti), cement (Rx vs Tb), and storage condition (dry [D] vs saline water [W]). Er:YSGG laser was applied at 6 W, 30% water-60% air, and 20 Hz (300 mJ/pulse energy) postcementation following a defined pattern. The force required to remove all the cemented copings from their abutments was measured on a universal testing machine (Instron model 4204). Descriptive statistics, multi-factor analysis of variance, and post hoc Tukey honest significant difference tests (α = .05) were performed. The mean peak force values at removal of the Zr abutment groups were 470.3 ± 151.33 N (ZrRxC), 161.7 ± 19.29 N (ZrRxD), 316.03 ± 95.24 N (ZrRxW), 103.27 ± 24.53 N (ZrTbC), 39.33 ± 6.21 N (ZrTbD), and 20.33 ± 6.45 N (ZrTbW); and for the Ti abutment groups were 349.80 ± 106.82 N (TiRxC), 84.63 ± 14.02 N (TiRxD), 177 ± 62.57 N (TiRxW), 54.77 ± 9.10 N (TiTbC), 22.67 ± 4.32 N (TiTbD), and 11.57 ± 2.30 N (TiTbW). Within the limitations of this study, it can be concluded that Er:YSGG laser allows for easier removal of cemented Zr copings with lower removal forces, with Ti abutment groups requiring lower forces than Zr abutment specimens. No significant difference was seen between laser and control groups for Tb compared to Rx. Er:YSGG laser shows great clinical promise for predictable retrievability of cemented, monolithic Zr implant crowns, especially with stronger resin-based cement such as Rx. With further clinical evidence, this could be very useful for clinicians managing cement-retained implant crown complications.