Publications
Showing 49 results for Author: Yiyu Wang
Sep, 2026
Conference Paper
Initial Thermal Evaluation of 422 Martensitic Stainless Steel Piston in a High-Output Diesel Engine
Jun, 2026
Journal
Creep-rupture behavior of alloy 740H weldment with alloy 263 filler metal.
The creep-rupture behavior of weldments of alloy 740H fabricated using shielded metal arc welding with a commercially available filler metal based on alloy 263 and a post-weld heat treatment of 800 °C/4 h was studied at 650, 750, and 850 °C. Stress levels were chosen to reach extended rupture lifetimes (up to over 71,000 h) relevant for long-term applications and pressure…
Mar, 2026
Conference Paper
Microstructure and Mechanical Performance of X120 Linepipe Steel in High-Pressure Hydrogen Gas
Mar, 2026
Conference Paper
An Engineering Approach for Weld Creep Lifetime Assessment Based on Local Property Measurement
The localized creep failure in the heat-affected zone (HAZ) of Grade 91 steel weldments has been identified as one of the most important factors causing significantly shortened service lifetime and structural integrity issues of welded components in advanced fossil and nuclear power plants. To conduct a reliable creep lifetime assessment, a new engineering assessment appro…
Mar, 2026
Conference Paper
Assessment of a Grade 91 Steel Forging and Seamless Pipe Section After 141,000-Hours of Operation in a Superheat Outlet Header
In this work, two unique heats of 9Cr creep strength enhanced ferritic (CSEF) steels extracted from a retired superheat outlet header after 141,000 hours of service were evaluated. These two CSEF steels were a forging manufactured to SA-182 F91 (F91) reducer and a seamless pipe produced to SA-335 P91 (P91) pipe. Their creep deformation and fracture behavior were assessed u…
Mar, 2026
Conference Paper
Scale-Up of Friction Self-piercing Riveting Process for Multi-material Joints
A single-class joining process known as “friction self-piercing riveting (F-SPR)” has been developed for joining various low-ductility lightweight materials on a laboratory scale. The frictional heat generated during the F-SPR process improved local ductility, resulting in crack-free joints and robust mechanical performance. This innovative joining technology was further a…
Mar, 2026
Conference Paper
Modeling-Based Design and Optimization of a Gradient Composite Transition Joint
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…
Mar, 2026
Journal
Spatially resolved phase transformation mapping in 410 Stainless Steel During Additive Manufacturing Visualized via Real-Time Infrared Data
In this study, we demonstrate that spatially resolved cooling curves derived from real-time infrared (IR) thermography during additive manufacturing (AM) can capture spatial variations in phase transformation temperatures through cooling curve analysis (CCA). Using this approach, we show that during laser hot-wire deposition of 410 stainless steel (410SS), the martensite s…
Feb, 2026
Journal
Elucidating microstructural evolution and hardness variation across friction self-piercing riveted Al-7055 using synchrotron X-ray scattering and advanced microscopy techniques
Friction self-piercing riveting (FSPR) is a unique hybrid joining technique that combines the advantages of mechanical interlocking, frictional heat, and solid-state joining (if metallurgically compatible) to produce crack free joints in high strength and/or low-ductility alloys at room temperature. In the current study, Al-7055 sheets were joined using FSPR for lightweigh…
Jan, 2026
Journal
Extended Continuous Cooling Transformation Diagram for 410 Stainless Steel encompassing δ→γ and γ→α′ Transformations Determined by Dilatometry
In this study, we use dilatometry to construct an extended Continuous Cooling Transformation (CCT) diagram for 410 stainless steel, capturing both δ→γ and γ→α′ transformations specifically for directed energy deposition (DED) additive manufacturing (AM) applications. To ensure that the findings are representative of AM specific microstructures and compositions, dilatometry…
Dec, 2025
Journal
Effect of post-weld heat treatment on microstructure and mechanical properties of rotary inertia friction welded dissimilar 422-4140 martensitic steel piston joints☆
The study investigated how post‐weld heat treatment (PWHT) temperature affects the microstructure and localized deformation/fracture during bend testing of rotary inertia friction welds (RIFW) between AISI 422 stainless steel and AISI 4140 steel. RIFW produced a fully martensitic interface with approximately 550 HV hardness in both the thermo-mechanically affected (TMAZ) a…