Publications
Showing 95 results for Author: Yan Chen
Sep, 2026
Journal
A strong and ductile Super Kovar alloy via fully coherent nanoprecipitates
Emerging high-precision technologies demand materials with exceptional dimensional stability and mechanical robustness, as even microscopic thermomechanical deformation can cause functional failure. However, a fundamental trilemma exists: High strength, ductility, and low thermal expansion are mutually exclusive, as strengthening-induced lattice distortions compromise the…
Sep, 2026
Journal
Atomic faulting drives exceptional toughness in low thermal expansion chromium alloys
Endowing functional properties with mechanical responses in traditional metals has been a frontier topic, akin to transforming base metal into gold. Chromium and its alloys, with their functional deficiencies and limited ductility, serve as typical examples. Herein, we report a Cr96Fe4Ge1.3B1 alloy that unifies low thermal expansion (LTE, αl = 1.79 × 10-6 K-1, 200 − 315 K)…
Sep, 2026
Journal
Effect of Collimation on Diffraction Signal-to-Background Ratios at a Neutron Diffractometer
High diffraction signal-to-background ratios (SBRs), the ratios of diffraction peak integrated intensity over its background intensity, are desired for a neutron diffractometer to acquire good statistics for diffraction pattern measurements and subsequent data analysis. For a given detector, while the diffraction peak signals primarily depend on the characteristics of neut…
Sep, 2026
Journal
Real-Time In Situ Neutron Diffraction Investigation of Phase-Specific Load Sharing in a Cold-Rolled TRIP Sheet Steel
Real-time in situ neutron diffraction was used to investigate the loading-direction dependence of phase-specific load sharing in a cold-rolled TRIP 780 sheet steel under tension at room temperature. A slightly lower yield stress and relatively faster initial strain hardening were observed for the tension along the rolling direction (RD), than those along the transverse dir…
Sep, 2026
Journal
Probing the fatigue enhancement in a thermally aged cast duplex stainless steel by in situ neutron diffraction
After long-term thermal aging at 400 °C for 3000 h and 10,000 h, a cast duplex stainless steel exhibits promoted fatigue performance, including enhanced three-stage cyclic hardening and prolonged fatigue life. Utilizing in situ neutron diffraction, the phase-specific stresses are resolved, and their evolutions over entire fatigue cycling reveal the underlying mechanisms of…
Sep, 2026
Journal
A Compact Cryogenic Environment for In Situ Neutron Diffraction Under Mechanical Loading
Understanding the deformation mechanisms of materials at cryogenic temperatures is crucial for cryogenic engineering applications. In situ neutron diffraction is a powerful technique for probing such mechanisms under cryogenic conditions. In this study, we present the development of a compact cryogenic environment (CCE) designed to facil-itate in situ neutron diffraction e…
Sep, 2026
Journal
Phase Stability and Electrochemical Performance of La-Site-Doped Li6La3Zr0.5Nb0.5Ta0.5Hf0.5O12 High-Entropy Garnets
We investigate La-site substitution in the high-entropy garnet Li6La3Zr0.5Nb0.5Ta0.5Hf0.5O12 (LLZNTH) using Ba2+, Sr2+, and Sm3+ to elucidate how dopant governs phase stability, Li-site distribution, and electrochemical behavior. X-ray diffraction shows that Sr2+ is incorporated homogeneously into the garnet lattice, whereas the larger Ba2+ and smaller Sm3+ ions partially…
Sep, 2026
Journal
Tracing Phase Transformation and Lattice Evolution in a TRIP Sheet Steel under High-Temperature Annealing by Real-Time In Situ Neutron Diffraction
Real-time in situ neutron diffraction was used to characterize the crystal structure evolution in a transformation-induced plasticity (TRIP) sheet steel during annealing up to 1000 °C and then cooling to 60 °C. Based on the results of full-pattern Rietveld refinement, critical temperature regions were determined in which the transformations of retained austenite to ferrite…
Sep, 2026
Conference Paper
Residual Stress Distribution in a Hydroformed Advanced High Strength Steel Component: Neutron Diffraction Measurements and Finite Element Simulations
Today’s automotive industry is witnessing increasing applications of advanced high strength steels (AHSS) combined with innovative manufacturing techniques to satisfy fuel economy requirements of stringent environmental regulations. The integration of AHSS in novel automotive structure design has introduced huge advantages in mass reduction while maintaining their structur…
Aug, 2026
Journal
A compact in situ polarized 3He neutron spin filter for the diffractometer VULCAN at the Spallation Neutron Source
We have built and commissioned a compact in situ 3He polarizer based on spin-exchange optical pumping for the engineering materials diffractometer, named VULCAN, at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. The system achieved 78% 3He polarization with a short pump-up time constant of 2.2 h. Its first deployment in an in situ half-polarized neut…
Aug, 2026
Journal
Tangent moduli and successive hardening mechanisms: quantification from in situ neutron diffraction and ductility improvement of nanoprecipitation-strengthened HEAs
According to the Considère criterion for necking, the improvement of tensile ductility can be accomplished by designing a number of hardening mechanisms that operate successively and thus sustain a continuously increasing work hardening rate (or at least not decreasing rapidly). This work proposes a novel mechanics approach to extract the tangent moduli of each constituent…