Tensile behavior of dual-phase titanium alloys under high-intensity proton beam exposure: Radiation-induced omega phase transformation in Ti-6Al-4V

OBJECTIVEStenoocclusive cerebral vasculopathy is an infrequent delayed complication of ionizing radiation. It has been well described with photon-based radiation therapy but less so following proton-beam radiotherapy. The authors report their recent institutional experience in evaluating and treating children with radiation-induced cerebral vasculopathy.METHODSEligible patients were age 21 years or younger who had a history of cranial radiation and subsequently developed vascular narrowing detected by MR arteriography that was significant enough to warrant cerebral angiography, with or without ischemic symptoms. The study period was January 2011 to March 2019.RESULTSThirty-one patients met the study inclusion criteria. Their median age was 12 years, and 18 (58%) were male. Proton-beam radiation therapy was used in 20 patients (64.5%) and photon-based radiation therapy was used in 11 patients (35.5%). Patients were most commonly referred for workup as a result of incidental findings on surveillance tumor imaging (n = 23; 74.2%). Proton-beam patients had a shorter median time from radiotherapy to catheter angiography (24.1 months [IQR 16.8–35.4 months]) than patients who underwent photon-based radiation therapy (48.2 months [IQR 26.6–61.1 months]; p = 0.04). Eighteen hemispheres were revascularized in 15 patients. One surgical patient suffered a contralateral hemispheric infarct 2 weeks after revascularization; no child treated medically (aspirin) has had a stroke to date. The median follow-up duration was 29.2 months (IQR 21.8–54.0 months) from the date of the first catheter angiogram to last clinic visit.CONCLUSIONSAll children who receive cranial radiation therapy from any source, particularly if the parasellar region was involved and the child was young at the time of treatment, require close surveillance for the development of vasculopathy. A structured and detailed evaluation is necessary to determine optimal treatment.

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Effect of peak stress and deformation history on the dynamic tensile behavior of a dual phase steel

10.1063/12.0000820 ◽

2020 ◽

Author(s):

J.P. Escobedo ◽

A.A.H. Ameri ◽

M. Gonzales ◽

R. Miller ◽

H. Wang ◽

...

Keyword(s):

Dual Phase Steel ◽

Peak Stress ◽

Tensile Behavior ◽

Dual Phase ◽

Deformation History ◽

Stress And Deformation

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Design and optimization study of a duoplasmatron ion source for high-intensity proton beam

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/j.nima.2021.165550 ◽

2021 ◽

pp. 165550

Author(s):

Bowen Zhou ◽

Hong Zhang ◽

Pengjiao Zhang ◽

Wenliang Li ◽

Sun An

Keyword(s):

Proton Beam ◽

High Intensity ◽

Ion Source ◽

Design And Optimization ◽

Optimization Study

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Phase Transformation and Tensile Behavior of Ti-22Al-25Nb Alloys with Bimodal Size Lamellar O-Phase Precipitates

Journal of Materials Engineering and Performance ◽

10.1007/s11665-021-05990-z ◽

2021 ◽

Author(s):

Bowen Xiong ◽

Kang Liu ◽

Zhenjun Wang ◽

Fang Peng

Keyword(s):

Phase Transformation ◽

Tensile Behavior ◽

O Phase

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Oxygen Induced Phase Transformation in TC21 Alloy with a Lamellar Microstructure

Metals ◽

10.3390/met11010163 ◽

2021 ◽

Vol 11 (1) ◽

pp. 163

Author(s):

Shu Wang ◽

Yilong Liang ◽

Hao Sun ◽

Xin Feng ◽

Chaowen Huang

Keyword(s):

Electron Microscopy ◽

Phase Transformation ◽

Oxygen Uptake ◽

Titanium Alloys ◽

Electron Backscatter Diffraction ◽

Lamellar Microstructure ◽

Α Phase ◽

Transmission Electron ◽

The Matrix ◽

Oxygen Ingress

The main objective of the present study was to understand the oxygen ingress in titanium alloys at high temperatures. Investigations reveal that the oxygen diffusion layer (ODL) caused by oxygen ingress significantly affects the mechanical properties of titanium alloys. In the present study, the high-temperature oxygen ingress behavior of TC21 alloy with a lamellar microstructure was investigated. Microstructural characterizations were analyzed through optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). Obtained results demonstrate that oxygen-induced phase transformation not only enhances the precipitation of secondary α-phase (αs) and forms more primary α phase (αp), but also promotes the recrystallization of the ODL. It was found that as the temperature of oxygen uptake increases, the thickness of the ODL initially increases and then decreases. The maximum depth of the ODL was obtained for the oxygen uptake temperature of 960 °C. In addition, a gradient microstructure (αp + β + βtrans)/(αp + βtrans)/(αp + β) was observed in the experiment. Meanwhile, it was also found that the hardness and dislocation density in the ODL is higher than that that of the matrix.

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