Study on the influence of post-processing parameters over microstructure and metallurgical properties of NiTi alloy

2020 ◽  
Author(s):  
Kiriti Mamidi ◽  
Himanth Talla ◽  
Bharath B. Ravichander ◽  
Behzad Farhang ◽  
Narges Shayesteh Moghaddam ◽  
...  
Keyword(s):  
Niti Alloy ◽  
Processing Parameters ◽  
Post Processing ◽  
Metallurgical Properties

scholarly journals Relevance of processing parameters for grain growth of metal halide perovskites with nanoimprint

2021 ◽  
Vol 127 (9) ◽  
Author(s):  
Andre Mayer ◽  
Tobias Haeger ◽  
Manuel Runkel ◽  
Johannes Rond ◽  
Johannes Staabs ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Secondary Growth ◽  
Processing Parameters ◽  
Post Processing ◽  
Perovskite Layer ◽  
Processing Step ◽  
Similar Preparation ◽  
Materials Used ◽  
Log Normal

AbstractThe quality and the stability of devices prepared from polycrystalline layers of organic–inorganic perovskites highly depend on the grain sizes prevailing. Tuning of the grain size is either done during layer preparation or in a post-processing step. Our investigation refers to thermal imprint as the post-processing step to induce grain growth in perovskite layers, offering the additional benefit of providing a flat surface for multi-layer devices. The material studied is MAPbBr3; we investigate grain growth at a pressure of 100 bar and temperatures of up to 150 °C, a temperature range where the pressurized stamp is beneficial to avoid thermal degradation. Grain coarsening develops in a self-similar way, featuring a log-normal grain size distribution; categories like ‘normal’ or ‘secondary’ growth are less applicable as the layers feature a preferential orientation already before imprint-induced grain growth. The experiments are simulated with a capillary-based growth law; the respective parameters are determined experimentally, with an activation energy of Q ≈ 0.3 eV. It turns out that with imprint as well the main parameter relevant to grain growth is temperature; to induce grain growth in MAPbBr3 within a reasonable processing time a temperature of 120 °C and beyond is advised. An analysis of the mechanical situation during imprint indicates a dominance of thermal stress. The minimization of elastic energy and surface energy together favours the development of grains with (100)-orientation in MaPbBr3 layers. Furthermore, the experiments indicate that the purity of the materials used for layer preparation is a major factor to achieve large grains; however, a diligent and always similar preparation of the layer is equally important as it defines the pureness of the resulting perovskite layer, intimately connected with its capability to grow. The results are not only of interest to assess the potential of a layer with respect to grain growth when specific temperatures and times are chosen; they also help to rate the long-term stability of a layer under temperature loading, e.g. during the operation of a device.

scholarly journals On the implementation of post-processing of runoff forecast ensembles

2021 ◽  
Author(s):  
Jon Olav Skøien ◽  
Konrad Bogner ◽  
Peter Salamon ◽  
Fredrik Wetterhall
Keyword(s):  
Initial Conditions ◽  
Processing Parameters ◽  
Forecast Errors ◽  
Post Processing ◽  
Continental Scale ◽  
Post Process ◽  
Global Calibration ◽  
Calibration Methods ◽  
Verification Period ◽  
Ensemble Model Output Statistics

AbstractDifferent post-processing techniques are frequently employed to improve the outcome of ensemble forecasting models. The main reason is to compensate for biases caused by errors in model structure or initial conditions, and as a correction for under- or overdispersed ensembles. Here we use the Ensemble Model Output Statistics method to post-process the ensemble output from a continental scale hydrological model, LISFLOOD, as used in the European Flood Awareness System (EFAS). We develop a method for local calibration and interpolation of the post-processing parameters and compare it with a more traditional global calibration approach for 678 stations in Europe based on long term observations of runoff and meteorological variables. For the global calibration we also test a reduced model with only a variance inflation factor. Whereas the post-processing improved the results for the first 1-2 days lead time, the improvement was less for increasing lead times of the verification period. This was the case both for the local and global calibration methods. As the post-processing is based on assumptions about the distribution of forecast errors, we also present an analysis of the ensemble output that provides some indications of what to expect from the post-processing.

scholarly journals Mechanical Properties of Additively Manufactured Thermoplastic Polyurethane (TPU) Material Affected by Various Processing Parameters

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3010
Author(s):  
Tao Xu ◽  
Wei Shen ◽  
Xiaoshan Lin ◽  
Yi Min Xie
Keyword(s):  
Mechanical Properties ◽  
Medical Devices ◽  
Thermoplastic Polyurethane ◽  
Critical Factor ◽  
Processing Parameters ◽  
Aerospace Engineering ◽  
Post Processing ◽  
Build Orientation ◽  
Good Biocompatibility ◽  
Material Tests

Thermoplastic polyurethane (TPU) is a polymer material that has high ductility, good biocompatibility and excellent abrasion resistance. These properties open a pathway to manufacturing functional TPU parts for applications in various fields such as aerospace engineering, medical devices and sports equipment. This study aims to investigate the mechanical properties of additively manufactured TPU material affected by three different processing parameters, including build orientation, mix ratio of the new and reused powders and post-processing. A series of material tests are conducted on TPU dumb-bell specimens. It is found that the mix ratio of the new powder is the most critical factor in improving the mechanical properties of the printed TPU parts. Compared to reused powder, new powder has better particle quality and thermal properties. Besides, build orientation is also a very important factor. TPU parts printed in flat and on-edge orientations show better tensile strength and deformability than those printed in upright orientation. In addition, post-processing is found to significantly enhance the deformability of TPU parts.

scholarly journals Microstructure and Corrosion Behavior of Ti-Nb Coatings on NiTi Substrate Fabricated by Laser Cladding

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 597
Author(s):  
Jie Hu ◽  
Yaojia Ren ◽  
Qianli Huang ◽  
Hao He ◽  
Luxin Liang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
Laser Processing ◽  
Niti Alloy ◽  
Processing Parameters ◽  
Medical Applications ◽  
Strengthening Effect ◽  
Aggressive Environment ◽  
Metallurgical Bonding ◽  
Fine Microstructure

Ti-23Nb (at.%) coatings on an NiTi alloy with metallurgical bonding were prepared by laser cladding (LC) technology using Ti-Nb mixture powders. The effects of laser processing parameters on the microstructure and mechanical properties of the coatings were systematically investigated and the corrosion resistance of the coatings was assessed. The coatings were composed of TiNb, (Ti, Nb)2Ni, and β-Nb phases. The coatings increased the hardness of the NiTi alloy by a combined strengthening effect of the eutectics and fine microstructure. The corrosion resistance of the coated part was improved. The coatings with great corrosion resistance could keep the coated parts inert in an aggressive environment, and effectively restrain the release of toxic Ni ions, which means that the Ti-Nb alloy coatings are likely to be used as a biomaterial for medical applications.

scholarly journals Intelligent post processing of seismic events

1994 ◽  
Vol 37 (3) ◽  
Author(s):  
T. Kvaerna ◽  
F. Ringdal
Keyword(s):  
Standard Deviation ◽  
Kola Peninsula ◽  
Broad Band ◽  
Region Of Interest ◽  
Mining Area ◽  
Processing Parameters ◽  
Post Processing ◽  
Mining Sites ◽  
Initial Event ◽  
Median Error

The Intelligent Monitoring Systern (IMS) currently provides for joint processing of data from six arrays located in Northern and Central Europe. From experience with analyst review of events automatically defined by the IMS, we bave realized that the quality of the automatic event locations can be significantly improved if the event intervals are reprocessed with signal processing pararneters tuned to phases from events in the given region. The tuned processing parameters are obtained from off line analysis of events located in the region of interest. The primary goal of such intelligent post processing is to provide event definitions of a quality that minimizes the need for subsequent manual analysis. The first step in this post processing is to subdivide the arca to be monitored in order to identify sites of interest. Clearly, calibration will be the easiest and potential savings in manpower are the largest for areas of high, recurring seismicity. We bave identified 8 mining sites in Fennoscandia/NW Russia and noted that 65.6% of the events of ML > 2.0 in this region can be associated with one of these sites. This result is based on 1 year and a half of data. The second step is to refine the phase arrival and azimuth estimates using frequency filters and processing parameters that are tuned to the initial event location provided by the IMS. In this study, we have analyzed a set of 52 mining explosions from the Khibiny Massif mining area in the Kola peninsula of Russia. Very accurate locations of these events bave been provided by the seismologists from the Kola Regional Seismology Centre. Using an autoregressive likelihood technique we have been able to estimate onset times to an accuracy (standard deviation) of about 0.05 s for P phases and 0.15 0.20 s for S phases. Using fixed frequency bands, azimuth can be estimated to an accuracy (one standard deviation) of 0.9 degrees for the ARCESS array and 3 4 degrees for the small array recently established near Apatity on the Kola peninsula. The third step in the post processing is a relocation of the event, using refined arrivai times and recomputed azimuths from broad band flk analysis. By introducing region specific travel time corrections, a median error of 1.4 km from the reported location has been obtained. This should be compared to the median error of 10.8 km for the automatie IMS processing for these events. This improvement in location accuracy clearly demonstrates the usefulness of the intelligent post processing approach.

Preparation and selective laser sintering of bamboo flour/copolyester composite and post-processing

2015 ◽  
Vol 30 (8) ◽  
pp. 1045-1055 ◽  
Author(s):  
Dejin Zhao ◽  
Yanling Guo ◽  
Kaiyi Jiang ◽  
Hui Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Strength ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Processing Parameters ◽  
Laser Sintering ◽  
Post Processing ◽  
New Type ◽  
Bamboo Flour

A new type of biocomposite, bamboo flour/copolyester (BFCP) composite for selective laser sintering (SLS™) was studied in this article. The bamboo flour was made from the bamboo residual of the bamboo production collected from a chopsticks factory. The BFCP composites of three mixture ratios (20/80, 25/75, and 30/70 (wt/wt)) were processed by SLS™. The proper processing parameters were determined by single-layer sintering methods. The mechanical properties of test specimens made from BFCP composites of three mixture ratios have been investigated. The results demonstrated that the mechanical properties of the specimens made by BFCP composite of 20/80 (wt/wt) were the best among those of the three mixture ratios and the average tensile strength, flexural strength, and impact strength of the specimens made from BFCP composite of 20/80 (wt/wt) were up to 4.14 MPa, 11.02 MPa, and 0.84 kJ m−2, respectively. The mechanical properties of specimens are extremely improved through infiltrating epoxy resin.

Investigating mechanical and thermo-physical properties of binder jet 3D printed elements using a statistical experiment approach

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bharath Seshadri ◽  
Kaushik Selva Dhanush Ravi ◽  
Illias Hischier ◽  
Arno Schlueter
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Physical Properties ◽  
Processing Parameters ◽  
Physical Characteristics ◽  
Post Processing ◽  
Statistical Experiment ◽  
Content Type ◽  
3D Printed ◽  
Thermo Physical Properties

Purpose With a growing list of available materials and processes, the inherent mechanical and thermophysical properties of three-dimensional (3D) prints are important design targets. This paper aims to study the functionality of binder jet 3D printed objects for thermally activated building construction elements and recyclable formwork for concrete structures. Design/methodology/approach Binder jet printed sand samples with various material and post-processing parameters (infiltration and baking) are prepared and studied. Using a statistical experiment design, the mechanical (flexural and compressive strength) and thermal (conductivity and specific capacity) characteristics are quantified. Findings Relative to the unprocessed “green” print samples, post-processing improved the flexural and compressive strength of the samples by factors of 6.9 and 21.6, respectively; the thermal conductivity and specific heat capacity were improved by factors of 7.7 and 1.2, respectively. For the investigated temperature range (20°C–200°C), the “green” prints showed excellent stability while the stability of post-processed samples depended on the infiltrate used. Microscopic images of the microstructures offered evidence to support improvement in the mechanical and thermo-physical characteristics of the 3D printed sand elements. Research limitations/implications The literature review concluded that optimal printing parameters and infiltration under vacuum could further improve the mechanical and thermo-physical properties of the binder jet printed elements. However, both these factors were not explored in this research. The statistical experimental design approach provided more flexibility to choose the number of experiments for a fixed amount of time and resources. However, for future work, a more extensive number of experiments and reproducibility testing for each combination of binder-infiltrate is recommended. Practical implications 3D printing has been identified as a promising opportunity to reduce material usage and improve construction efficiency in the field of architecture and building engineering. The emerging fabrication technologies are further expected to significantly reduce the operational energy of buildings through performance integration, i.e. multi-functional building elements with integrated heat- and mass-transfer capabilities to replace conventional systems. Originality/value This study has quantified the impact of infiltration on the mechanical and thermo-physical characteristics of sand-printed elements and, as such, reports reproducible functional performance maps for sand-print applications. The research demonstrates a way to achieve the desired functional characteristics of 3D prints through combinations of material selection and process/post-processing parameters.

Influence of Post-Processing and the Type of Filling on Strength Properties of Elements Printed by Stereolithography Technology

2021 ◽  
Vol 326 ◽  
pp. 51-60
Author(s):  
Ewelina Wacławik-Macura ◽  
Mariusz Król
Keyword(s):  
Continuous Process ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Processing Parameters ◽  
Strength Properties ◽  
Bending Test ◽  
Post Processing ◽  
Three Point Bending ◽  
Cad System ◽  
Uv Lamps

The application of stereolithography, gives the possibilities to manufacture components with complex shape, during one continuous process based on the prepared virtual model in CAD system. The paper presents the results of experimental tests for samples printed using Low Force Stereolithography (LFS)TM technique, using Rigid 4000 Resin, Formlabs company. The experimental studies used unconventional post-processing, which consists in extending the exposure to UV lamps, without the application of heating. In the next step, optimized post processing parameters were used to manufacture components with different types and degrees of filling - linear and hexagonal. In the experiment, the samples were testes to a tensile strength test and a three-point bending test. The goal of the experiment was to select optimal parameters for post-processing and element design to reduce the component weight.

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