The application potential of additive manufacturing nickel-based superalloys in aeroengines and gas turbines is extensive, and evaluating their mechanical properties is crucial for promoting the engineering application in load-bearing components. In this study, Hastelloy X alloy was prepared using the laser powder bed fusion process combined with solution heat treatment. The tensile and high cycle fatigue properties were experimentally investigated at room temperature as well as two typical elevated temperatures, 650 °C and 815 °C.
View Article and Find Full Text PDFPhilos Trans A Math Phys Eng Sci
January 2024
The large scatter in high-cycle fatigue (HCF) life poses significant challenges to safe and reliable in-service assessment of additively manufactured metal components. Previous investigations have indicated that inherent manufacturing defects are a critical factor affecting the fatigue performance of the components, and the HCF life is significantly influenced by the geometric parameters of the critical defects inducing crack nucleation. Therefore, it is highly important to elucidate the correlation of the HCF life with the geometric parameters of critical defects.
View Article and Find Full Text PDFThis paper investigates the effects of defects on tensile failure of additive manufactured AlSi10Mg alloy focusing particularly on the role of large pancake shaped loss of fusion (LOF) defects lying perpendicular to the build direction (BD). Time-lapse in situ synchrotron radiation X-ray micro-computed tomography during straining reveals how, when tested parallel to the BD, the LOF defects extend laterally with straining connecting to other defects and giving rise to low plasticity and an essentially brittle failure mode. When they are aligned edge-on to the straining direction, failure is characterised by a ductile cup-cone failure with significant elongation of the defects axially and extensive necking prior to failure.
View Article and Find Full Text PDFCracking from a fine equiaxed zone (FQZ), often just tens of microns across, plagues the welding of 7000 series aluminum alloys. Using a multiscale correlative methodology, from the millimeter scale to the nanoscale, we shed light on the strengthening mechanisms and the resulting intergranular failure at the FQZ. We show that intergranular AlCuMg phases give rise to cracking by micro-void nucleation and subsequent link-up due to the plastic incompatibility between the hard phases and soft (low precipitate density) grain interiors in the FQZ.
View Article and Find Full Text PDFBackground/aim: Prostate cancer (PC) is one of the major diseases that affects male health and ranks as the second most frequent cancer in men worldwide. Although most newly-diagnosed PCs are well-differentiated tumors with a high cure probability, there are some patients with aggressive malignancies that show potential for recurrence and metastasis. Cytotoxic T lymphocytes are a specific immune effector cell population that mediates immune responses against cancer.
View Article and Find Full Text PDFBackground/aim: Cancer stem cells (CSCs) have been suggested playing a crucial role in the tumorigenesis and tumor progression. Clinically, concurrent chemoradiotherapy (CCRT) after transurethral resection of the bladder is the widely accepted treatment option for high-grade bladder urothelial carcinoma (UC); however, a proportion of bladder UC patients still suffer from recurrence and metastasis. In the present study, we investigated the stemness properties of bladder UC cells with respect to various disease stages.
View Article and Find Full Text PDFRationale: Malakoplakia and xanthogranulomatous pyelonephritis are chronic inflammatory conditions of the kidney characterized by the infiltration of inflammatory cells.
Patient Concerns: An 82-year-old female patient had a history of hypertension, type 2 diabetes mellitus, dyslipidemia, and end-stage renal disease under hemodialysis. She was admitted repeatedly 4 times within 4 months due to urosepsis.
Gradient structure (GS) is commonly designed and processed in engineering materials to improve mechanical properties especially fatigue performance by taking advantage of the strengthened surface. However, whether the very-high-cycle fatigue (VHCF) property can be improved by GS is questioning due to the different crack initiation mechanisms between low-, high-cycle and VHCF. In this paper, GS of a Ti-6Al-4V alloy is generated by pre-torsion and characterized by electron backscatter diffraction.
View Article and Find Full Text PDFUreteral tumor is prone to result in lumen obstruction. Villous adenoma is most frequently found in the colon and rectum, seldom in the urinary tract and even more rarely in the ureter or pelvis. Herein, we present a case of bilateral renal stones of more than 10 years' duration with the chief complaint of right flank pain.
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