Basket Weave Research Articles

Effect of Near-Isothermal Forging Temperature on the Microstructure and Mechanical Properties of Near α High Temperature Titanium Alloy

The effect of near-isothermal forging temperature on the microstructure and mechanical properties of Ti-Al-Sn-Zr-Mo-Nb-W-Si-Er near α high temperature titanium alloy was investigated by near-isothermal forging at the strain rate of 0.01s-1 and 80% deformation. The results indicated that near-isothermal forging temperature of 1050°C is relatively low. After forging at 1050°C the grain growth is not obvious and original β grain as well as intragranular lamellar are fine. By comparison, the alloy forged at 1120°C possessed typical basket weave microstructure. With the increase of near-isothermal forging temperature, the tensile strength and plasticity of the alloy decrease. Excellent comprehensive mechanical properties could be achieved in the alloy after forging at temperature 1050°C.

Microstructural heterogeneity in rate-dependent plasticity of multiphase titanium alloys

Polycrystalline rate-dependent plasticity is found to originate from heterogeneous slip system/phase rate response. Micro-mechanism under low stress and low temperature (T< 0.3Tm) has been shown to be different from conventional rate sensitivity expectations. Hence the constitutive framework developed is dependent on the crystallographic orientation, properly capturing micro-scale anisotropic rate behaviour.The intrinsic rate anisotropy of the HCP α prism and basal and BCC β phase slip systems in Ti-6242, recently determined from micro-pillar and crystal plasticity modelling, have been utilised to investigate the structural strain rate sensitivities of colonies, polycrystals, bimodal and basket weave microstructures.The rate sensitivity of colony structures is dominated by the HCP α phase behaviour, at least for alloys containing up to ∼20% volume fraction β phase, and is largely independent of β-lath orientation. The apparent anisotropy of a1, a2 and a3 basal resolved shear stresses in Ti-6242 colonies is shown to originate from the local crystal stress states established as opposed to the α−β interfaces.Texture and α−β morphology are shown to affect rate dependence and to corroborate that the basal rate sensitivity is stronger than that for prism slip in Ti-6242. Morphological effects are shown to affect rate dependence but not strongly, but the number of HCP α phase variants in basketweave structures is found to have a significant effect with higher numbers of variants leading to lower strain rate sensitivities. This is potentially important in designing alloys to resist cold dwell fatigue.

Microstructural Evolution of the Interdiffusion Zone between U-9 Wt Pct Mo Fuel Alloy and Zr-1 Wt Pct Nb Cladding Alloy Upon Annealing

Diffusion couple formed between U-9 wt pct Mo and Zr-1 wt pct Nb alloys, proposed as fuel and clad materials, respectively, in nuclear research reactors, was annealed to investigate the microstructural evolution of the interdiffusion zone (IZ) as a function of temperature. A layered-type IZ microstructure was observed, the mechanism of development of which was elucidated. Mo2Zr phase, present as dispersoids, in the U-rich part of the as-bonded IZ evolved into a continuous layer and into a “massive” morphology upon annealing. The discontinuous precipitation reaction in the matrix adjoining the Mo2Zr phase, instigated by Mo depletion, generated lamellae of α-U phase within the γ-U(Mo,Zr) matrix. Zr-rich α-Zr(U) precipitates were observed in U-rich U-Mo-Zr matrix in the IZ next to the U-9Mo base material due to the clustering tendency of the matrix phase. The IZ next to Zr-1Nb base material comprised a “basket weave” microstructure of α-Zr laths with β-Zr(Nb,U) interlath boundaries, wherein an omega like transformation of the latter to δ-UZr2 was also noticed. The growth rates of the IZ were orders of magnitude lower when compared with the ones reported between the compositionally similar U-10 wt pct Mo alloy and the presently used Al or Al-Si cladding alloys.

A truly Lego®-like modular microfluidics platform

Ideally, a modular microfluidics platform should be simple to assemble and support 3D configurations for increased versatility. The modular building blocks should also be mass producible like electrical components. These are fundamental features of world-renowned Legos® and why Legos® inspire many existing modular microfluidics platforms. In this paper, a truly Lego®-like microfluidics platform is introduced, and its basic feasibility is demonstrated. Here, PDMS building blocks resembling 2 × 2 Lego® bricks are cast from 3D-printed master molds. The blocks are pegged and stacked on a traditional Lego® plate to create simple, 3D microfluidic networks, such as a single basket weave. Characteristics of the platform, including reversible sealing and automatic alignment of channels, are also analyzed and discussed in detail.

Design and manufacture of 3D rectangular box-shaped fabrics

Multi-ply woven fabric consists of many layers and can be used to form three-dimensional shapes, which finds its application in a variety of end-uses. One of the advantages is that this type of products requires no seams or cuts. This paper presents a novel method to facilitate the design of 3D rectangular box-shaped fabrics made of multi-ply weaves. A preliminary folding-down process is a must for fabric manufacture and two folding approaches were developed accordingly. Approach A has been found to be more suitable for boxes with X ≥ 2Z. The elimination of quadruple-layer fabric region simplifies the design and weaving process. In this regard, plain weave was used sections form box body and basket weave was employed for bound-layer regions so that fabric recoiling could be avoided. The diagonal lines connecting the bound-layer and double-layer regions is required to have an angle of 45°, and hence a Jaquard loom was in use for manufacturing. As the fabric is formed by different parts, thread density varies, leading to uneven yarn tension. This problem can be solved using additional warp beams. Approach B requires the two side planes to be folded in, the design process of which is similar to that of approach A. Theoretically, boxes with multiple cells could also be designed using this technique. Approach A has been found to be able to deal with boxes of various geometrical parameters. One problem of the 3D fabric is the soft edges, which requires further investigations.

Microstructural Evolution and Mechanical Properties of Laser Processed Ti6Al4V Sheets

This paper reports on the evolved microstructure and the mechanical properties of laser beam formed Ti6Al4V sheets processed at different parameters. Effective control of the process parameters is essential in achieving the desired properties for tailored applications. In addition, it will be easier to control one or two process parameters in order to achieve the expected material property than multiple parameters. The samples were produced by varying the laser power and the number of scans. The results revealed that controlling only the laser power during the forming process, the physical, mechanical and the microstructural properties of the processed materials could be effectively monitored and controlled. The micrograph shows an alpha and beta basket weave microstructure. The dark beta phase is finely embedded in the alpha phase. It was observed that the alpha-beta basket weave microstructure is denser at lower laser power. This implies that as the laser power increases, the density of the acicular alpha phase decreases; this is often attributed to the increased cooling effect during the laser forming process. It was observed that the Vickers microhardness value of the laser formed Ti6Al4V sheets at a constant scan speed of 0.05 m/min, increases as the laser power increases from 1000W to 1200W due to laser-material interaction. Similarly, the calculated UTS for the laser beam formed Ti6Al4V sheets increased as the Vickers microhardness value increases.

Microstructural evolution and mechanical property of Ti-6Al-4V wall deposited by continuous plasma arc additive manufacturing without post heat treatment

Plasma arc additive manufacturing (PAM) is a novel additive manufacturing (AM) technology due to its big potential in improving efficiency, convenience and being cost-savings compared to other AM processes of high energy bea\\m. In this research, several Ti-6Al-4V thin walls were deposited by optimized weld wire-feed continuous PAM process (CPAM), in which the heat input was gradually decreased layer by layer. The deposited thin wall consisted of various morphologies, which includes epitaxial growth of prior β grains, horizontal layer bands, martensite and basket weave microstructure, that depends on the heat input, multiple thermal cycles and gradual cooling rate in the deposition process. By gradually reducing heat input of each bead and using continuous current in the PAM process, the average yield strength (YS), ultimate tensile strength (UTS) and elongation reach about 877MPa, 968MPa and 1.5%, respectively, which exceed the standard level of forging. The mechanical property was strengthened and toughened due to weakening the aspect ratio of prior β grains and separating nano-dispersoids among α lamellar. Furthermore, this research demonstrates that the CPAM process has a potential to manufacture or remanufacture in AM components of metallic biomaterials without post-processing heat treatment.

Mechanical behavior of woven natural fiber fabric composites: Effect of weaving architecture, intra-ply hybridization and stacking sequence of fabrics

A comprehensive analysis carried out on the mechanical and free vibration properties of woven natural fiber polymer composites is presented. Jute fabric with three different weave types (plain, basket and herringbone) and intra-ply woven jute-banana fabrics are considered for investigation of the effect of weave type of a fabric and its stacking sequence on mechanical, dynamic mechanical and free vibration properties. Enhancement of the properties is found with the number of layers of fabric and better properties obtained for four layers. Uniform stress distribution along warp and weft direction of fabric with basket weave type lead to better properties compared to other weave types for four-layered composites. Intra-ply hybridization of jute-banana also enhances the mechanical properties but slightly less than the jute-basket fabric composite. The investigations on effect of layer sequence of fabrics revealed improvement in mechanical properties. Layered composite with relatively strong intra-ply fabric as the facing layer and relatively weak jute plain fabrics as the core layer has higher tensile and flexural properties. Experimental modal analysis carried out on beam-like composite laminates reveal that natural frequencies and associated modal damping factor are significantly influenced by stacking sequence and weave type of a fabric. The density of the composite calculated based on Archimedes principle matches well with the theoretical values.

The Effect of Various Weave Designs on Mechanical Behavior of Lamina Intraply Composite Made from Kenaf Fiber Yarn

The development of lamina intraply composite is a novel approach that can be adopted to address the challenges of balance mechanical properties of polymer composite. This research will focuses on the effects of weave designs on the mechanical behavior of a single ply or also known as lamina intraply composite. The six (6) specimens of lamina intraply composites were made by kenaf fiber as a reinforcement and unsaturated polyester resin as a matrix in various weave designs which were plain, twill, satin, basket, mock leno and leno weave. The vacuum infusion technique was adopted due to advantages over hand lay-up. It was found that the plain, twill and satin weave exhibited better mechanical properties on tensile strength. The fiber content of the specimen was 40% and the result of the resin content of the specimen was 60% due to the higher permeability of natural fiber.

The Effect of Lamina Intraply Hybrid Composites on the Tensile Properties of Various Weave Designs

The topic of natural fiber is one of the most active areas in thermoset composite research today. This paper will focuses on the effect of weave designs on the mechanical behaviour of lamina intraply hybrid composites. Twelve specimens were used and they were made of kenaf fibre and glass fibre as a reinforcement and unsaturated polyester resin as a matrix in various weave designs which were plain, twill, satin, basket, mock leno, and leno weave. Vacuum infusion technique was used due to its superior advantages over hand lay-up. The specimens were produced in two types which were kenaf fibre in warp direction interlace with glass fibre in weft direction (WK-WG) and glass fibre in warp direction interlace with kenaf fibre in weft direction (WG-WK). Various weave designs were found to affect the tensile properties. Glass fibre in warp direction has a greater effect on tensile strength compared to kenaf fibre in warp direction. Mock leno weave exhibited better mechanical properties for WK-WG and WG-WK, about 54.74 MPa and 99.46 MPa respectively.

Microstructure and Mechanical Properties of Friction Stir Welded Dissimilar Titanium Alloys: TIMET-54M and ATI-425

Weight reduction in automobiles and in aerospace industries can profoundly register for the behemoth change in the consumption of the fossil fuels and, in turn, CO2 emission. With a promising hope in hindsight for weight reduction, we have successfully produced butt joints of friction stir welded (FSWed) dissimilar, and rather novice, α-β titanium alloys—ATI-425 and TIMET-54M. The study presented in this article encompasses the microstructural and mechanical properties of the joints for two cases, (1) ATI-425 on the advancing side; and (2) TIMET-54M on the advancing side. The evolution of microstructure and concomitant mechanical properties are characterized by optical microscopy, microhardness, and tensile properties. A detailed description of the microstructural evolution and its correlation with the mechanical properties have been presented in this study. Our investigations suggest that mixing patterns are dependent on the location (advancing, or retreating) of the alloying sheet. However, the microstructure in the weld nugget (WN) is quite similar (grain boundary α, and basket weave morphology consisting of α + β lamellae) in both cases with traces of untransformed β. The thermo-mechanically affected zone (TMAZ) on the either side of the weld is primarily affected by the microstructure of the base material (BM). A noticeable increase in the hardness values in the WN is accompanied by significant deflection on the advancing and retreating sides. The tensile properties extracted from the global stress strain curves are comparable with minimal difference for both cases. In both cases, the fracture occurred on the retreating side of the weld.

Phase Field Simulations of Autocatalytic Formation of Alpha Lamellar Colonies in Ti-6Al-4V

We present phase field simulations incorporating contributions due to chemical free energy, anisotropic interfacial energy, and elastic energy due to transformation strain, to demonstrate the nucleation and growth of multiple variants of alpha from undercooled beta in Ti-6Al-4V under isothermal conditions. A new composite nucleation seeding approach is used within the phase field simulations to demonstrate that the presence of a pre-existing strain field can cause the nucleation of specific crystallographic variants of alpha based on minimization of local elastic strain energy. Under conditions where specific combinations of elastic strains exist, for example in the vicinity of one or more pre-existing alpha variants, the nucleation of a new alpha variant is followed by the successive nucleation of the same variant in the form of a lamellar colony by an autocatalytic mechanism. At a given thermodynamic undercooling, the colony structure was favored at a nucleation rate that was low enough to allow sufficient growth of previously nucleated variants before another nucleus formed in their vicinity. Basket weave morphology was formed at higher nucleation rates where multiple nuclei variants grew almost simultaneously under evolving strain fields of several adjacent nuclei.

When to suspect tinea; a histopathologic study of 103 cases of PAS-positive tinea.

The histopathologic features of tinea vary widely and its diagnosis could be easily missed if the index of suspicion is not high. We aimed in this study to detect histopathologic features that could be a clue for diagnosis We retrospectively reviewed 103 cases of tinea, confirmed by Periodic acid-Schiff (PAS) staining. For each case, gender, biopsy site, and pre-biopsy suspicion were recorded. The presence or absence of 17 microscopic features was noted. Concordance between pre-biopsy and histopathologic diagnosis was noted in 57.28% of cases, suggesting that the diagnosis is often not suspected clinically. Among the histopathologic features studied, a compact stratum corneum (either uniform or forming a layer beneath a basket weave stratum corneum), parakeratosis, mild spongiosis and neutrophils in the stratum corneum and within the blood vessels were the most frequent features noted. This study suggests histopathologic clues that should prompt the pathologist to order a PAS stain, especially when diagnosis is not suspected clinically.

Primary phase growth and microstructure evolution of rapidly solidifying ternary Ti-12Al-8V alloy

Liquid Ti-12Al-8V alloy was rapidly solidified by electromagnetic levitation and drop tube techniques. The levitation processing avoided the violent heterogeneous nucleation of primary β phase and led to an actual maximum undercooling of 212K (0.11TL). The primary β dendrites exhibited a high growth velocity up to 14.9m/s but subsequently transformed into basket weave structures. Drop tube experiments indicated that the final microstructure morphology was determined by the coupled influences of undercooling extent and cooling rate. If the cooling rate exceeded 3.31×103K/s, the primary β phase was retained metastably to ambient temperature.

Sliding wear behavior of laser-nitrided and thermal oxidation-treated Ti–5Al–5Mo–5V–1Cr–1Fe alloy fabricated by laser melting deposition

Sliding wear behavior of laser-nitrided and thermal oxidation-treated Ti–5Al–5Mo–5V–1Cr–1Fe (TC18) alloy fabricated by laser melting deposition (LMD) has been investigated to improve on wear resistance of laser melting deposited titanium alloy. The microstructure, wear morphology, hardness and wear rate were examined for the unmodified, laser-nitrided and thermal oxidation-treated LMD Ti–5Al–5Mo–5V–1Cr–1Fe alloy. As compared to α/β basket weave microstructure with fine lamellar α (hcp) observed on the unmodified LMD Ti–5Al–5Mo–5V–1Cr–1Fe alloy, Ti, Ti2N and TiN were formed on the LMD specimens after laser nitriding. After thermal oxidation, a surface layer composed of rutile TiO2 was formed on the LMD specimens along with coarsening of α lath. The increase in hardness and wear resistance of the laser-nitrided LMD Ti–5Al–5Mo–5V–1Cr–1Fe alloy is attributed to hard dendritic TiN formed on the specimens. The wear rate of the thermal oxidation-treated LMD specimens was <1 % of that of the unmodified LMD specimens when hardness of the former was twice as much as the latter. The superior sliding wear resistance of the thermal oxidation-treated LMD specimens is attributed to the presence of the lubricious rutile oxide layer and hardened diffusion zone.

Influence of Electric Pulse Heat Treatment on the Dynamic Mechanical Behavior of TC6 Titanium Alloy

In order to improve the dynamic mechanical properties of TC6 titanium alloy, the effect of electric pulse heat treatment on the dynamic properties and microstructures of TC6 has been investigated in this paper. It was observed that the secondary α phase was successfully controlled through rapid temperature rising and proper temperature holding by the electric pulse. Compared with traditional heat treatment methods, the electric pulse treatment can obviously refine the grains of secondary α phase. In addition, the refined second α phase distributed uniformly with fine equiaxed and lamellar shapes. As a result, this refined second α phase will resist the expansion of cracks and promote the coordination deformation of grains. According to the dynamic compression test results, it can be found that the adiabatic shear susceptibility of the microstructure obtained from the electric pulse treatment obviously decreased. On the other hand, the dynamic ductility and absorbed energy were much higher than that of the microstructure (equiaxed, bi-modal and basket weave structures) obtained from traditional heat treatments.

"Basket weave technique" for medial patellofemoral ligament reconstruction: Clinical outcome of a prospective study.

Background:Bone tunneling and implants with rigid fixations for medial patellofemoral ligament (MPFL) reconstruction are known to compromise results and are avoidable, especially in skeletally immature subjects. This study was to assess if these deficiencies were overcome with the technique devised by the author which avoids implants and bone tunnels. Results were assessed for complication rate and outcome.Materials and Methods:Fifty six knees of recurrent lateral patellar dislocation were treated in the past 49 months by MPFL reconstruction. Thirty nine were female and 17 male knees. The mean age was 20.6 years (range 9-48 years). Mean followup was 26 months. Five knees had previously failed stabilization procedures. Thirty one cases had Dejours Type A or B and 12 had Type C trochlear dysplasia. Arthroscopy was performed for associated injuries and loose bodies. Seven knees required loose body removal. Five knees underwent lateral retinacular release. Four knees had tibial tuberosity transfer. One knee had an associated anterior cruciate ligament reconstruction. An anatomical MPFL reconstruction was performed using hamstring autograft without the need for intraoperative fluoroscopy. Only soft tissue fixation was necessary with this newly devised technique and suturing. A rapid rehabilitation protocol was implemented with monthly followup until normalcy and 6 monthly thereafter.Results:All achieved full range of motion and normal mediolateral stability. There was no recurrence of dislocation. No major surgery related complications. One patella fracture at 8 months was due to a fall developed terminal restriction of flexion. Those in sports could return to their sporting activities (Tegner 1–9). Cases with osteochondral fractures had occasional pain that subsided in 1 year. Mean Kujala score improved from 64.3 to 99.69 with KOOS score near normal in all.Conclusion:This new method of MPFL reconstruction gives excellent results. It avoids complications related to bone tunneling and implants. It is a safe, effective, reliable and reproducible technique.

Tensile properties and fracture characteristics of TC18 alloy by electron beam wire deposition

In order to provide guidance for the regulation of mechanical properties of TC18 titanium alloy built by electron beam wire deposition (EBWD), the fracture mechanism of the alloy has been investigated. The EBWD TC18 alloy exhibits columnar β-grains growing opposite to the heat flow. The microstructure is composed of basket weave microstructures and grain boundary α-phases. The rupture of EBWD TC18 alloy originates at the grain boundary and is prone to propagate along the grain boundary α-phases, leading to decrease in elongation of the alloy. The fracture property of the EBWD TC18 alloy is mainly ductile fracture, which is broken by both normal stress and shear stress. The fracture mechanism is a mixture of intergranular-ductile fracture and transgranular-dimple fracture.

Normal Vulvar Histology: Variation by Site.

The aim of the study was to assess the histology of normal vulvar skin with attention to anatomic location and epithelium type. We performed a retrospective histologic review of 118 vulvar biopsies and excisions obtained between 2010 and 2014 with adjacent normal skin or mucosa. Exclusions included age younger than 18 years, vestibulectomy, labiaplasty, inflammatory dermatoses, and insufficient normal tissue for assessment. Stratum corneum morphology was assessed as basket weave, compact, or intermediate. Stratum granulosum cell layer number and epithelial thickness were recorded. Dermal lymphocytic infiltrate was described as nil, sparse, moderate, or dense. Fischer exact test, Pearson χ, and Student t test were used for statistical analysis. There were 7 cases from mons pubis, 11 from perineum, 83 from labia, and 17 from vestibule. In the skin, the stratum corneum morphology was basket weave in 31%, compact in 35%, and intermediate in 34%. Stratum corneum at the mons pubis was uniformly basket weave, whereas at perineum, it was either compact or intermediate (7/7 vs 0/11; p < .001); the labia demonstrated all 3 morphologies. Parakeratosis (PK) was identified at the specimen edge in 4 cases of hairless skin and 7 cases of squamous mucosa. Mean epithelial thickness and dermal lymphocytic infiltration were similar in specimens with and without PK. Compact stratum corneum of vulvar skin and a zone of PK at the mucocutaneous junction may be normal histological findings. Pathologists need to be aware of site-related differences of the vulvar epithelium to avoid overdiagnosis of pathological conditions.

Development of Deflection Prediction Model for Concrete Block Pavement Considering the Block Shapes and Construction Patterns

Concrete block pavement (CBP) is distinct from typical concrete or asphalt pavements. It is built by using individual blocks with unique construction patterns forming a discrete surface layer to bear traffic loadings. The surface structure of CBP varies depending on the block shapes and construction patterns, so it is hard to apply a general equivalent elastic modulus estimation method to define the surface structural strength. In this study, FEM analysis and dynamic loading test were carried out to develop a deflection prediction model for CBP considering the block shapes and construction patterns. Based on the analysis results, it was found that block shapes did not have much effect on load distribution, whereas construction patterns did. By applying the deflection prediction model to the rutting model for CBP proposed by Sun, the herringbone bond pattern showed the best performance comparing with stretcher bond or basket weave bond pattern. As the load repetition increased to 1.2 million, the rutting depth of CBP constructed by herringbone bond pattern was 2 mm smaller than those constructed by the other two patterns.