bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Reheated CGHAZ Microstructure on Hydrogen-Induced Cracking Susceptibility in SA-508 Steel
Authors: Romero Fernando , Siefert William , McCracken Steven L. , Alexandrov Boian 
Published: October 2024

Abstract
According to ASME Case N-888-3, Similar and Dissimilar Metal Welding Using Ambient Temperature SMAW or Machine GTAW Temper Bead Technique, a 48 hr waiting period before conducting the final nondestructive examination (NDE) is required when ferritic filler weld metal is used. The purpose of the 48 hr hold is to confirm the absence of hydrogen-induced cracking in the temper bead heat-affected zone. In previous research, the effect of post-weld heat treatment (PWHT) and temper bead welding (TBW) on the hydrogen-induced cracking (HIC) susceptibility in the coarse-grained heat-affected zone (CGHAZ) in welds of SA-508, P-No. 3 Group 3, pressure vessel steel was investigated using the Delayed Hydrogen Cracking Test (DHCT). In that previous study, the Gleeble thermomechanical simulator was used to generate six CGHAZ microstructural conditions: as-welded (AW), PWHT, and AW with single a TBW reheat at 675, 700, 725, and 735°C. Hydrogen was introduced to the specimen through cathodic charging under in situ constant tensile stress. The HIC susceptibility for these microstructures was ranked by the DHCT at a diffusible hydrogen level significantly exceeding typical GTAW and SMAW processes. The work described in this paper investigates the susceptibility to HIC of these same CGHAZ microstructures with DHCT at variable current densities, further ranking each condition. Test results were analyzed by fracture surface examination of failed tests, and cross-section microstructural analysis under a scanning electron microscope (SEM). Future steps include evaluating critical hydrogen content levels using gas chromatography for each condition. The results from this study will be used to consider potential elimination of the NDE hold time requirement in Case N-888-3 when ferritic weld metal is used.
Nondestructive Detection of Creep Damage in ASME Grade 91 Steel Welds
Authors: Sawada Kota , Taniuchi Yasushi , Nojima Takehiro , Kimura Kazuhiro , Kimura Takahiro , Nomura Kyohei , Saito Noriko , Morita Akira , Hayakawa Hiroyuki , Sugiuchi Takao , Ohbitsu Kazushige , Yaguchi Masatsugu , Nishizawa Koju , Ozaki Hiroshi , Fukunishi Hayato , Ohi Kouji , Nishioka Tomoya , Emi Naoya , Okada Hirokazu , Komai Nobuyoshi , Hayashi Kyohei , Tominaga Kimihiko 
Published: October 2024

Abstract
This study evaluates various nondestructive testing methods for detecting creep damage and assessing residual life in Grade 91 steel welds. Three primary detection techniques were investigated: phased array ultrasonic testing (PAUT), eddy current testing with high-temperature superconductor direct current and superconducting quantum interference device (ECT•HTS-dc-SQUID), and replica observation. PAUT detected creep damage between 60-80% of creep life, while ECT•HTS-dc-SQUID showed detection capability between 80-90% of creep life. Replica observation revealed creep voids only in the final stages before rupture. Additionally, three strain measurement methods were evaluated: capacitive strain sensors (providing continuous monitoring during creep exposure), laser displacement meters (used during test interruptions), and SPICA strain measurement. Both capacitive sensors and laser meters produced results comparable to conventional extensometer measurements. The SPICA method proved particularly effective in measuring heat-affected zone (HAZ) strain after creep exposure, revealing higher strain values in the HAZ compared to base and weld metal, with a consistent increase during creep exposure.
Assessment of 316H Stainless Steel Produced by Directed Energy Deposition Additive Manufacturing for High Temperature Power Plant Applications
Authors: Sutton Ben , Jang Eun , Tate Stephen , Shingledecker John 
Published: October 2024

Abstract
This study evaluates the elevated temperature mechanical performance of 316H stainless steel produced using directed energy deposition (DED) additive manufacturing (AM) from three separate collaborative research programs focused on understanding how AM variables affect creep performance. By combining these studies, a critical assessment of variables was possible including the DED AM method (laser powder and gas metal arc wire), laser power, sample orientation relative to build orientation, chemical composition, and post-processing heat treatment. Detailed microstructure characterization was used to supplement creep and chemistry results to provide insights into potential mechanistic differences in behavior. The study found that sample orientation was a critical variable in determining lower-bound creep behavior, but that in general the lowest creep strength orientation and the lowest creep ductility orientation were not the same. Heat treatment was also an important variable with as-printed materials showing for specific test conditions improved performance and that underlying substructures formed due to inhomogeneous chemical distributions were not completely removed when using standard wrought solution annealing heat-treatments. The chemistry of the final deposited parts differed from the starting stock and may be an important consideration for long-term performance which is not fully appreciated. Overall, the study found that while all the DED materials tested fell within an expected wrought scatter band of performance, the actual creep performance could vary by an order of magnitude due to the many factors described.
Materials Technology for Innovative Thermal Power Generation System Toward Carbon Neutrality in Japan
Authors: Takeyama Masao 
Published: October 2024

Abstract
For future carbon neutral society, a novel thermal power generation system with no CO2 emission and with extremely high thermal efficiency (~ 70 %) composed of the oxygen/hydrogen combustion gas turbine combined with steam turbine with the steam temperature of 700°C is needed. The key to realize the thermal power plant is in the developments of new wrought alloys applicable to both gas turbine and steam turbine components under higher temperature operation conditions. In the national project of JST-Mirai program, we have constructed an innovative Integrated Materials Design System, consisting of a series of mechanical property prediction modules (MPM) and microstructure design modules (MDM). Based on the design system, novel austenitic steels strengthened by Laves phase with an allowable stress higher than 100 MPa for 105 h at 700°C was developed for the stream turbine components. In addition, for gas turbine components, novel solid-solution type Ni-Cr-W superalloys were designed and found to exhibit superior creep life longer than 105 h under 10 MPa at 1000°C. The superior long-term creep strengths of these alloys are attributed to the “grain-boundary precipitation strengthening (GBPS)” effect due to C14 Fe2Nb Laves phase and bcc α2-W phase precipitated at the grain boundaries, respectively.
Qualifying Additively Manufactured Eurofer97 Reduced Activation Steel for Fusion
Authors: Turk Andrej , Lenka Shaumik , Patil Dhairyasheel , Balachandran-Nair Shanoob , Churchman Callum , Gullane Alex , Crudden David 
Published: October 2024

Abstract
To operate future fusion power plants economically, the fusion community needs structural materials that can last longer and operate at higher temperatures than current materials, as well as better heat-dissipating components and a reliable supply chain for them. Additive manufacturing (AM) of existing reduced activation ferritic/martensitic steels (RAFMS) has the potential to solve these problems, which is why we developed a laser powder bed fusion (LPBF) process for Eurofer97 steel, demonstrating excellent mechanical properties (~30% improved yield strength, ~6300% improved creep rupture life, similar toughness and ductility compared to wrought Eurofer97) and low process scatter (relative standard error for yield, tensile strength and elongation on build plate &lt;1%). The main remaining challenge is the consistent sourcing of quality Eurofer97 powder, but we have shown that this can already be done if the limits on impurity elements are slightly relaxed. Our work lays the groundwork for the manufacture of complex fusion components that can dissipate heat better and have a higher operating temperature thanks to the improved material properties. It also helps plug the current RAFMS supply chain gap, enabling easier component prototyping and small-scale manufacture that can smoothly scale in volume in the future.
Claddings, Coatings, and Surface Modification: Load Behavior of Hardfaced Sealing Surfaces of Fittings
Authors: Elsen-Humberg Stephan , Unterumsberger Fabian 
Published: October 2024

Abstract
High-pressure valves and fittings used in coal-fired 600/625 °C power plants are hardfaced for protection against wear and corrosion and to provide optimum sealing of the guides and seats. Stellite 6 and Stellite 21 are often used for hardfacing, which is carried out by build-up welding, usually in several layers. The valve materials are generally heat-resistant steels such as 10CrMo9-10 (1.7380), X20CrMoV1 (1.4922), or Grade 91 / Grade 92 (1.4903 / 1.4901). In recent years, cracks or delaminations have frequently occurred within the hardfaced layer. The influence of cycling operation is not well understood. Other essential factors are the chemical composition of the base material and of the filler metal; especially in terms of the resulting iron dilution during the deposition of the welding overlays. The research project was initiated to investigate the crack and delamination behavior and to understand the involved damage mechanisms. Thermostatic and cyclic exposure tests have shown that cracking is favored by the formation of brittle phases due to iron dilution from the substrate material during the manufacturing process. Recommendations for the welding process of hardfaced sealing surfaces of fittings were derived from the investigation results.
Phase-Field Modeling of Diffusion Bonding in 316H Stainless Steel for Nuclear Engineering Applications
Authors: Wang Rui , Wang Peng , Allen Todd R. , Gao Fei , Bhatt Sagar , Messner Mark C. , Jentz Ian W. 
Published: October 2024

Abstract
Diffusion bonding is a key manufacturing process for nucleation applications including compact heat exchangers. Accurately predicting the alloy's behavior during the diffusion bonding process presents challenges, primarily due to the intricate interplay of microstructural evolution and physical processes such as compressive loading, temperature history, and component migration. The current study develops a phase-field model designed to simulate the diffusion bonding in 316H stainless steel, a material with exceptional high-temperature strength, corrosion resistance and suitability to high-pressure conditions. Our model incorporates a multi-phase, multi-component framework that aligns the experimental observations with the grain growth and heterogeneous nucleation, where arbitrary external compressive load and temperature history are considered. The simulations focus on grain nucleation, growth, and microstructure evolutions across diffusion bonding line under a variety of temperature profiles, mechanical loads, and surface roughness conditions, mirroring experimental setups. Our model predicts consistent simulation results with experiments in terms of the grain size and distribution near the bonding area, offering a better understanding of the diffusion bonding mechanism and the manufacturing process for building reliable compact heat exchangers.
Creep-Fatigue Interaction Life and Prediction Model Based on Stress Relaxation Ratio of Nickel-Based Superalloy 617
Authors: WU Haili , SUN Lingen , MEI Linbo 
Published: October 2024

Abstract
Creep-fatigue tests strain-controlled with different strain amplitudes and different hold times at 725 were done on nickel-based alloy 617 as a typical candidate material for turbine rotor of advanced ultra-supercritical power plant. Stress relaxes during the hold time when the strain remains at the tensile peak. The analysis of the stress relaxation during different strain hold times shows that the ratio of the relaxation stress and the maximum stresses has strong correlation with strain amplitude and hold time. The failure life also has a certain dependence on the relaxation stress ratio. The failure life decreases and the relaxation stress ratio increases as the strain amplitude increases. The failure life decreases and the relaxation stress ratio increases as the hold time increases. Therefore the stress relaxation ratio was used as an intermediate variable to obtain the corresponding relationship model by establishing the relationship between the relaxation stress ratio and the strain and the relationship between the relaxation stress ratio and the failure life. This model can be used to predict the creep-fatigue interaction life more simply and directly.
Oxidation and Mechanical Properties of Ultrafine-Grained MoSiBTiC Alloy Produced by Rapid Solidification
Authors: Yoshimi Kyosuke , Abe Naoma , Nan Xi , Ida Shuntaro , Wada Takeshi , Kato Hidemi 
Published: October 2024

Abstract
The microstructural evolution of the MoSiBTiC alloy by rapid solidification and its effect on oxidation and mechanical properties were investigated in this study. A Mo-5Si-10B-10Ti-10C (at%) alloy was produced by a conventional arc-melting technique in an Ar atmosphere, and then it was rapidly solidified by tilt-casting into a rod-shaped copper hearth. Vickers hardness values increased drastically above 1000 Hv due to the microstructure refinement through rapid solidification. They rose from the center toward the outer surface, ranging from about 1100 to 1300 Hv. Interestingly, the oxidation resistance of the rapidly solidified MoSiBTiC alloy at 1100 °C was dramatically improved, probably due to the microstructure refinement effect with ultrafine grains. However, the fracture toughness value of the rapidly solidified MoSiBTiC alloy was about 8 MPa·m1/2, less than half of the cast and heat-treated MoSiBTiC alloy previously reported. Heat treatment and composition optimization will further improve the performance of the rapidly solidified MoSiBTiC alloy.
Statistical Analysis and Effect of Product Chemistry and Grain Size on the High Temperature Creep Properties of 316 Stainless Steels
Authors: Zhang Shutong , Bridges Alex , Shingledecker John , Lolla Tapasvi , Acharya Rohan 
Published: October 2024

Abstract
This study investigates the influences of product chemistry and grain size on the high-temperature creep properties of 316 stainless steels by analyzing an extensive range of historical and modern literature data. The investigated 316 stainless steel creep property dataset, including more than 160 heats and 2,400 creep testing data, covers a wide spectrum of elemental compositions and product forms. To perform a prudent analysis of the creep property dataset, a statistical overview was first implemented to understand the data distribution relevant to data sources, chemistries, product forms, testing temperatures, and grain sizes. The creep data of 550°C, 600°C, 650°C, 700°C, and 750°C with ±10°C were grouped together, and the analytical study was performed on each sub dataset to investigate the temperature-specific creep performance. The creep strength was evaluated using the average stress ratio (ASR) between the experimental and predicted creep data of tested 316SS heats. The influence of composition and grain size on the creep strength ratio were evaluated using linear correlation analysis. Effects of specified and non-specified elements including C, N, and B were specifically investigated to understand their impacts on the creep strength with regards to the variation of creep temperature. In addition to the literature data, the most recent EPRI creep data of three commercial heats were used to validate the correlations from the historical creep property dataset.
Modeling-Based Design and Optimization of a Gradient Composite Transition Joint
Authors: Zhang Wei , Wang Yiyu , Wang Yanli , Feng Zhili , Hu Shanshan , Liu Xingbo , Qian Haiyang 
Published: October 2024

Abstract
An innovative additively manufactured gradient composite transition joint (AM-GCTJ) has been designed to join dissimilar metals, to address the pressing issue of premature failure observed in conventional dissimilar metal welds (DMWs) when subjected to increased cyclic operating conditions of fossil fuel power plants. The transition design, guided by computational modeling, developed a gradient composite material distribution, facilitating a smooth transition in material volume fraction and physical properties between different alloys. This innovative design seeks to alleviate structural challenges arising from distinct material properties, including high thermal stress and potential cracking issues resulting from the thermal expansion mismatch typically observed in conventional DMWs. In this study, we investigated the creep properties of transition joints comprising Grade 91 steel and 304 stainless steel through a combination of simulations and creep testing experiments. The implementation of a gradient composite design in the plate transition joint resulted in a significant enhancement of creep resistance when compared to the baseline conventional DMW. For instance, the creep rupture life of the transition joint was improved by &gt; 400% in a wide range of temperature and stress testing conditions. Meanwhile, the failure location shifted to the base material of Grade 91 steel. Such enhancement can be primarily attributed to the strong mechanical constraint facilitated by the gradient composite design, which effectively reduced the stresses on the less creep-resistant alloy in the transition zone. Beyond examining plate joints, it is crucial to assess the deformation response of tubular transition joints under pressure loading and transient temperature conditions to substantiate and demonstrate the effectiveness of the design. The simulation results affirm that the tubular transition joint demonstrates superior resistance compared to its counterpart DMW when subjected to multiaxial stresses in tubular structures. In addition, optimization of the transition joint’s geometry dimensions has been conducted to diminish the accumulated deformation and enhance the service life. Lastly, the scalability and potential of the innovative transition joints for large-diameter pipe applications are addressed.
Rancangan Model PIS Berbasis Teori Belajar Psikologi Humanistik Abraham Harold Maslow pada Mata Pelajaran Matematika
Authors: Sumadi Suhartini , Fitriani Anis Alfian , Putra Teguh Yuliandri , Ardiansyah Fuad 
Published: October 2024

Rumusan masalah dari penelitian ini adalah “bagaimana perancangan model PIS (Pembelajaran Inklusi Sosial) berbasis Teori Belajar Psikologi Humanistik Abraham Harold Maslow pada mata pelajaran matematika?”. Penelitian ini pada hakikatnya merupakan penelitian pengembangan. Dalam penelitian ini, menjelaskan terkait model penelitian pengembangan terbaru yakni model C-ID (Contruct, Instructional, and Design). Perumusan model PIS (pembelajaran inklusif sosial) pada mata pelajaran matematika berbasis teori belajar psikologi humanistik Abraham Harold Maslow, yaitu meliputi: 1) landasan filosofi pembelajaran, yaitu merujuk dari teori humanistik dengan pendekatan pembelajaran, yaitu pembelajaran inklusif, pembelajaran aktif, kreatif, kolaboratif, kooperatif dan demokratis; 2) implementasi berupa tahap persiapan atau perencanaan, tahap proses pembelajaran yang sesuai dengan sintak pembelajaran, sistem sosial berupa demokratif, dialogis, kooperatif, bertanggungjawab, merata, sistem pendukung berupa perangkat pembelajaran, LKPD, materi pembelajaran matematika, ice breaking berbasis humanistik, dan dampak instruksional dan pengiring berupa kemampuan memahami, mengimplementasikan konsep matematika, dan memecahkan persoalan yang didukung dengan sikap toleran, kerjasama, setia kawan, demokratis, kerja keras, kritis, mandiri, terbangunnya sikap bangga, percaya diri, kompetitif, solidaritas, dan responsif; dan 3) evaluasi yang terdiri dari evaluasi proses melalui pengamatan kinerja dan pemahaman peserta didik dan evaluasi hasi melalui tes unjuk kerja peserta didik.Kata Kunci: Inklusi Sosial, Model PIS, Teori Humanistik
Eksplorasi Etnomatematika terhadap Masjid Jami Cikini Al-Ma’mur sebagai Media dalam Penyampaian Konsep Geometri
Authors: Soebagyo Joko , Haya Aqiela Fadia 
Published: October 2024

Etnomatematika dapat menjadi penghubung antara pembelajaran matematika sekolah dengan kebudayaan sehari-hari. Konsep matematika pada artefak budaya dapat dijadikan media pembelajaran sehingga peserta didik mendapatkan dua atau lebih pengetahuan sekaligus, minimal budaya dan matematika. Kota Jakarta memiliki salah satu bangunan bersejarah, yaitu Masjid Jami Cikini Al-Ma’mur yang sudah berdiri sejak tahun 1840. Penelitian ini memiliki tujuan untuk mengeksplorasi etnomatematika pada struktur bangunan Masjid Jami Cikini Al-Ma’mur yang dapat dijadikan sebagai media penyampaian konsep matematika khususnya konsep geometri. Pendekatan penelitian kualitatif dengan jenis etnografi digunakan untuk mengeksplorasi konsep matematika pada Masjid Jami Cikini Al-Ma’mur. Jenis data yang dikumpulkan terdiri dari data primer dan sekunder, di mana teknik pengumpulannya melalui observasi, wawancara dan dokumentasi. Berdasarkan hasil penelitian menunjukkan bahwa struktur bangunan Masjid Jami Cikini Al-Ma’mur sebagian besar terdapat etnomatematika pada konsep geometri seperti persegi, trapesium, segitiga siku-siku, tabung, prisma, translasi, rotasi, setengah lingkaran, persegi panjang, refleksi, limas, balok, dilatasi, jajar genjang, bola, belah ketupat, lingkaran. Konsep matematika tersebut diantaranya berasal dari pintu utama masjid, jendela masjid, tiang penyangga, bagian tempat wudhu, pagar masjid menunjukkan konsep geometri bangun ruang, bangun datar dan transformasi.Kata Kunci: Etnomatematika, Geometri, Masjid Jami Cikini Al-Ma’mur