Search Results - "StJohn, David H"

Additive manufacturing of ultrafine-grained high-strength titanium alloys by Zhang, Duyao, Qiu, Dong, Gibson, Mark A., Zheng, Yufeng, Fraser, Hamish L., StJohn, David H., Easton, Mark A.

“…Additive manufacturing, often known as three-dimensional (3D) printing, is a process in which a part is built layer-by-layer and is a promising approach for…”
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A real-time synchrotron X-ray study of primary phase nucleation and formation in hypoeutectic Al–Si alloys by Prasad, Arvind, McDonald, Stuart D., Yasuda, Hideyuki, Nogita, Kazuhiro, StJohn, David H.

“…This work reports the results of real-time X-ray radiography of grain refined and unrefined Al–Si alloys solidified at the SPring-8 synchrotron. The nucleation…”
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Effect of Ni, Zn, Au, Sb and In on the Suppression of the Cu3Sn Phase in Sn-10 wt.%Cu Alloys by Mehreen, Syeda U., Nogita, Kazuhiro, McDonald, Stuart D., Yasuda, Hideyuki, StJohn, David H.

“…Since manufacturing is transitioning into Pb-free solder development for electronic assembly and packaging, consumer demands for more compact electronics have…”
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Corrosion resistance of aged die cast magnesium alloy AZ91D by Song, Guangling, Bowles, Amanda L, StJohn, David H

“…The corrosion behaviour of die cast magnesium alloy AZ91D aged at 160 °C was investigated. The corrosion rate of the alloy decreases with ageing time in the…”
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Effect of manganese on grain refinement of Mg–Al based alloys by Cao, Peng, Qian, Ma, StJohn, David H.

“…Manganese is a grain refiner for high purity Mg–3%Al, Mg–6%Al, Mg–9%Al, and commercial AZ31 (Mg–3%Al–1%Zn) alloys when introduced in the form of an Al–60%Mn…”
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Mechanism for grain refinement of magnesium alloys by superheating by Cao, Peng, Qian, Ma, StJohn, David H.

“…The mechanisms for grain refinement of magnesium alloys by superheating have remained ambiguous since 1931. A model has been proposed on the basis of the…”
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Observation and Prediction of the Hot Tear Susceptibility of Ternary Al-Si-Mg Alloys by Easton, Mark A., Wang, Hao, Grandfield, John, Davidson, Cameron J., StJohn, David H., Sweet, Lisa D., Couper, Malcolm J.

“…An investigation into the hot tear susceptibility of ternary Al-Si-Mg alloys has been made using direct crack observation, measurement of load response, and…”
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Tailoring hierarchical microstructures and nanoprecipitates in additive-manufactured Al-Zn-Mg-Cu-Nb alloys for simultaneously enhancing strength and ductility by Xiao, Fei, Shu, Da, Wang, Yixiao, Sun, Qinyao, Wang, Donghong, Yang, Chao, Wang, Shubin, Mi, Jiawei, Sun, Baode, StJohn, David H.

“…Additive manufacturing provides an efficient way of producing metallic components with complex geometries. Their microstructure is substantially different to…”
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Native grain refinement of magnesium alloys by Cao, Peng, Qian, Ma, StJohn, David H.

“…High purity Mg–Al type alloys have a naturally fine grain size compared to commercial purity alloys with the same basic composition. This is referred to as…”
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Real time synchrotron X-ray observations of solidification in hypoeutectic Al–Si alloys by Nogita, Kazuhiro, Yasuda, Hideyuki, Prasad, Arvind, McDonald, Stuart D., Nagira, Tomoya, Nakatsuka, Noriaki, Uesugi, Kentaro, StJohn, David H.

“…This paper demonstrates how recent advances in synchrotron technology have allowed for the real-time X-ray imaging of solidification in Al–Si alloys, despite…”
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Effect of ultrasonic treatment on the alloying and grain refinement efficiency of a Mg – Zr master alloy added to magnesium at hypo- and hyper-peritectic compositions by Nagasivamuni, B., Wang, Gui, StJohn, David H., Dargusch, Matthew S.

“…[Display omitted] •UST applied to Mg – Zr alloys improved the alloying efficiency of the Zr master alloy.•UST reduced the amount of Zr sludge and increased…”
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Grain Refinement of Alloys in Fusion-Based Additive Manufacturing Processes by Zhang, Duyao, Prasad, Arvind, Bermingham, Michael J., Todaro, Carmelo J., Benoit, Michael J., Patel, Mitesh N., Qiu, Dong, StJohn, David H., Qian, Ma, Easton, Mark A.

“…One of the less desirable aspects of fusion-based additive manufacturing is the propensity for coarse columnar grain structures crossing build layers to form…”
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Ultrauniform, strong, and ductile 3D-printed titanium alloy through bifunctional alloy design by Zhang, Jingqi, Bermingham, Michael J, Otte, Joseph, Liu, Yingang, Hou, Ziyong, Yang, Nan, Yin, Yu, Bayat, Mohamad, Lin, Weikang, Huang, Xiaoxu, StJohn, David H, Dargusch, Matthew S

“…Coarse columnar grains and heterogeneously distributed phases commonly form in metallic alloys produced by three-dimensional (3D) printing and are often…”
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Peritectic phase formation kinetics of directionally solidifying Sn-Cu alloys within a broad growth rate regime by Mehreen, Syeda U., Nogita, Kazuhiro, McDonald, Stuart D., Yasuda, Hideyuki, StJohn, David H.

“…Previous studies have shown that the peritectic transformation may not occur and, depending on the cooling rate, the peritectic phase can nucleate and grow…”
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Effect of Cooling Rate on the Grain Refinement of Mg-Y-Zr Alloys by Sun, Ming, StJohn, David H., Easton, Mark A., Wang, Ke, Ni, Jiaming

“…The grain refinement resulting from the addition of yttrium (Y) (1, 3 pct, and 9 wt pct) and zirconium (Zr) (0.1, 0.2, and 0.5 wt pct) to magnesium (Mg) under…”
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The effect of ultrasonic treatment on the mechanisms of grain formation in as-cast high purity zinc by Nagasivamuni, B., Wang, Gui, StJohn, David H., Dargusch, Matthew S.

“…[Display omitted] •Ultrasonic treatment (UST) of high purity Zn produced a grain refined structure.•Macrostructures have columnar, refined equiaxed and mixed…”
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Refining prior-β grains of Ti–6Al–4V alloy through yttrium addition by Zhang, Duyao, Qiu, Dong, Gibson, Mark A., Zheng, Yufeng, Fraser, Hamish L., Prasad, Arvind, StJohn, David H., Easton, Mark A.

“…Significant prior-β grain refinement of as-cast Ti–6Al–4V alloy was achieved through additions of yttrium. Microstructural analysis revealed three mechanisms…”
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Nucleation and grain formation of pure Al under Pulsed Magneto-Oscillation treatment by Liang, Dong, Liang, Zhuyuan, Zhai, Qijie, Wang, Gui, StJohn, David H.

“…The grain structure of commercially pure Al can be significantly refined by the Pulsed Magneto-Oscillation (PMO) treatment. When PMO was applied to the melt…”
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The Interdependence model of grain nucleation: A numerical analysis of the Nucleation-Free Zone by Prasad, Arvind, Yuan, Lang, Lee, Peter D., StJohn, David H.

“…Predictions by a 1-D analytical model and a 3-D numerical model of the formation of the Nucleation-Free Zone (NFZ) surrounding each growing grain during the…”
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Eutectic grains in unmodified and strontium-modified hypoeutectic aluminum-silicon alloys by MCDONALD, Stuart D, DAHLE, Arne K, TAYLOR, John A, STJOHN, David H

“…Additions of strontium to hypoeutectic aluminum-silicon alloys modify the morphology of the eutectic silicon phase from a coarse platelike structure to a fine…”
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