Chen-Wei Shao

• PhD
• Research Associate at University of Toronto

This study compares the fatigue life of a 7475-T7351 aluminum alloy lower wall plate in an aircraft beam structure under alternating corrosion and fatigue conditions to universal fatigue life. It incorporates a corrosive environment and variable amplitude fatigue loads. The current study uses the “beach marking” technique and visual inspection to m...

ABSTRACT The microstructure and notch tensile fracture morphologies at different stress concentration factors of the low alloy steel 35CrMo for the head cover bolts of the pump turbine of a storage power station were investigated by electron backscatter diffraction microscopy and scanning electron microscopy. The effects of tempering temperature on...

The hydrogen embrittlement (HE) behavior of a selective laser-melted (SLM) 316L austenitic stainless steel has been investigated by hydrogen charging experiments and slow strain rate tensile tests (SSRTs) at room temperature. The results revealed that compared to the samples without H, the ultimate tensile strength (UTS) and elongation (EL) of spec...

Nanostructured materials are being actively developed, while it remains an open question how to rapidly scale them up to bulk engineering materials for broad industrial applications. This study propose an industrial approach to rapidly fabricate high-strength large-size nanostructured metal matrix composites and attempts to investigate and optimize...

It remains an intricate problem how to enhance low-cycle fatigue (LCF) performance, in the premise of guaranteeing a relatively high strength (or cyclic stress) which is vital to long-time service, for engineering components. The underlying cause of this puzzle is the lack of practical theory on cracking evolution/life prediction for LCF. In this s...

The mechanical response of a Co11.3Cr20.4Fe22.6Mn21.8Ni23.9 (wt%) high entropy alloy with a segmented coarse grain structure is investigated using strain-rate-dependent uniaxial compression experiments. The composition is verified using ab-initio simulations by examining thermal stability through the reduction of Gibbs free energy relative to simil...

This study developed microstructure-based finite element (FE) models to investigate the behavior of cold-sprayed aluminum–alumina (Al-Al2O3) metal matrix composite (MMC) coatings subject to indentation and quasi-static compression loading. Based on microstructural features (i.e., particle weight fraction, particle size, and porosity) of the MMC coa...

We present a combined experimental and computational investigation of the mechanical properties of a CoCrFe0.75NiMo0.3Nb0.125 (composition in molar ratio) high-entropy alloy additively manufactured via cold spray. We find that the sprayed alloy exhibits extraordinary mechanical properties under compression, reaching yield stress of ~ 1745 MPa, ulti...

A study on the microstructure and composition, micro-hardness and strain-rate-dependent compressive behaviors, and the associated failure mechanisms of an ultra-lightweight Mg-Li-Al alloy were conducted. X-ray diffraction and X-ray photoelectron spectroscopy showed a multi-phase material with ~35 wt% Li and ~20 wt% Al, and a dendritic "fishbone" mi...

This study developed microstructure-based finite element (FE) models to investigate the behavior of cold-sprayed aluminum-alumina (Al-Al2O3) metal matrix composite (MMCs) coatings subject to indentation and quasi-static compression. Based on microstructural features (i.e., particle weight fraction, particle size, and porosity) of the MMC coatings,...

Aluminum-alumina (Al–Al2O3) composites with ultrahigh strength were designed by combining dispersion strengthening via the addition of Al2O3 particles and matrix strengthening via in situ strain hardening. Cold spraying additive manufacturing technology was applied to fabricate the composites. The yield strength (σ0.2%) of the Al-46 wt.% Al2O3 comp...

As important lightweight structural materials, cast aluminum alloys have been largely used in the transportation and aerospace industries. In general, Al–Si-based alloys comprise more than 90% of all castings due to their excellent castability and corrosion resistance. However, even though various reinforcements have been introduced, the strength o...

Surface decarburization directly influences the service performance of spring steel, which is an important scientific issue. The bending fatigue behavior of 50CrMnMoVNb spring steel with surface decarburization as well as treated by surface spinning strengthening (3S) was systematically investigated in this study. The results show that the decarbur...

We report a novel method, named as stepping refining (STR) processing, to prepare three-dimensional nanograined bulk of high-Mn twinning-induced plasticity (TWIP) steel for the first time. After STR processing, the average grain size reduces to 20 nm—which is smaller than any reported grain size of TWIP steel—and the hardness reaches to 5.8 GPa, ap...

We report a method, named as T & A treatment, to improve the high-cycle fatigue (HCF) property of twinning-induced plasticity (TWIP) steel without sacrificing its ductility and work-hardening ability. A long-range gradient in grain size was obtained in the TWIP steel, whose HCF resistance is better than both coarse-grain and fine-grain steels, brea...

A novel method named as surface spinning strengthening (3S) is proposed to achieve gradient microstructures in the surface layer of a high-Mn twinning induced plasticity (TWIP) steel. A hardened layer with depth larger than 1 mm is found in the 3Sed sample, accompanied by a gradient grain-size transition from ~300 nm to ~50 µm. In comparison with t...

Enhancing strength-ductility synergy of materials has always been a hot but difficult topic in material science, for most structural materials, steels in particular, it is inevitable to sacrifice ductility when increasing strength, and vice versa. In this study, by introducing a linear gradient in grain size into Fe-Mn-C twinning-induced plasticity...

We report that materials with similar tensile properties can also exhibit quite different low-cycle fatigue (LCF) performances. Experimental results demonstrate that the LCF properties of twinning induced plasticity (TWIP) steels are naturally dominated by microscopic deformation mechanisms (mainly dislocation slip mode), which slightly influences...

We find the existing empirical relations based on monotonic tensile properties and/or hardness cannot satisfactorily predict the low-cycle fatigue (LCF) performance of materials, especially for twinning-induced plasticity (TWIP) steels. Given this, we first identified the different deformation mechanisms under monotonic and cyclic deformation after...

Compared to stress controlled high-cycle fatigue, enhancing strain controlled low-cycle fatigue (LCF) properties of material is much more difficult and less reported. In this study, we introduced two strategies and technologies to improve the LCF performance of Fe-Mn-C twinning induced plasticity (TWIP) steel. One is grain refining without introduc...

The low-cycle fatigue (including extremely-low-cycle fatigue) behaviors of the Fe[single bond]Mn[single bond]C TWIP steels are comprehensively investigated focusing on the effects of the imposed strain amplitude and Mn content on the deformation and damage characteristics. It is found that fatigue performance varies obviously with increasing Mn con...

The cyclic deformation and damage behaviors of the Fe-Mn and Fe-Mn-C TRIP/TWIP steels are comprehensively studied in a wide range of strain amplitude (from 0.3% to 8.0%). It is found that with increasing C content, the dislocation structures change from wavy slip to planar slip after cyclic deformation. In order to evaluate the low-cycle and extrem...

The tensile properties, high-cycle fatigue properties, and microstructure evolutions during fatigue process of as-received and pre-strained Fe-30Mn-0.9C twinning-induced plasticity (TWIP) steel were investigated. It is found that the fatigue lives of the TWIP steel can be effectively improved through pre-straining, since the deformation twins induc...

Cyclic deformation and damage behavior of a Ni-free high-nitrogen austenitic stainless steel with a composition of Fe-18Cr-18Mn-0.63N (weight pct) were studied, and the internal stress and effective stress were estimated by partitioning the hysteresis loop during cyclic straining at total strain amplitudes ranging from 3.0 × 10−3 to 1.0 × 10−2. It...

Uniaxial tensile and compressive deformation behaviors of Fe-18Cr-18Mn-0.63N high-nitrogen austenitic stainless steel were investigated at different strain rates. It is found that, with increasing strain rate, the yield strength of the steel increases either under tension or compression, while the ultimate tensile strength and the total elongation...

Structural change of an AuCu intermetallic alloy cluster including 249 atoms during heating is studied by molecular dynamics simulation within the framework of embedded atom method. The analyses of pair-distribution function, atomic density function, and pair analysis technique show that the structural change of this cluster involves different stag...