scholarly journals Effect of Cerium and Magnesium on Surface Microcracks of Al–20Si Alloys Induced by High-Current Pulsed Electron Beam

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 61
Author(s):  
Liang Hu ◽  
Bo Gao ◽  
Ning Xu ◽  
Yue Sun ◽  
Ying Zhang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Alloy Surface ◽  
Homogeneous Distribution ◽  
Anticorrosion Property ◽  
High Current ◽  
Pulsed Electron Beam ◽  
Mg2si Phase ◽  
Primary Si ◽  
Microcrack Propagation ◽  
Brittle Phase

The effect of Ce and Mg on surface microcracks of Al–20Si alloys induced via high-current pulsed electron beam (HCPEB) was studied. Mg was revealed to refine the primary Si phase in the pristine microstructure by forming a Mg2Si phase, leading to the suppression of microcrack propagation within the brittle phase after HCPEB irradiation. The incorporation of Ce into the Al–Si–Mg alloys further refined the primary Si phase and reduced the local stress concentration in the brittle phase induced by HCPEB irradiation. Ultimately, the surface microcracks were observed to be eliminated by the synergistic effects between the two elements. For Al–20Si–5Mg–0.7Ce alloys, Ce demonstrated a homogeneous distribution in the Al matrix on the HCPEB-irradiated alloy surface, while the Mg and Si exhibited a certain degree of aggregation in the Mg2Si phase. Metastable structures were formed on the HCPEB-irradiated alloy surface, including the nano-primary silicon phase, nano-cellular aluminium structure, and nano-Mg2Si phase. Compared with alloy specimens containing Mg, the Al–20Si–5Mg–0.7Ce alloy specimens exhibited an excellent anticorrosion property after HCPEB irradiation mainly due to the combined effects of the grain refinement and microcrack elimination.

scholarly journals Halo Evolution of Hypereutectic Al-17.5Si Alloy Treated with High-Current Pulsed Electron Beam

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
L. Hu ◽  
B. Gao ◽  
J. K. Lv ◽  
S. C. Sun ◽  
Y. Hao ◽  
...  
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Electron Beam ◽  
Alloy Surface ◽  
High Current ◽  
Pulsed Electron Beam ◽  
Relative Wear Resistance ◽  
Multiple Pulses ◽  
Diffraction Peaks ◽  
Bull's Eye

Halo evolution of an Al-17.5Si alloy surface after treatment with increasing pulse numbers of a high-current pulsed electron beam (HCPEB) was investigated. A halo is a ring microstructure resembling a bull’s eye. SEM results indicate that the nanocrystallization of halo induced by HCPEB treatment leads to gradual diffusion of the Si phase. Multiple pulses numbers cause the Si phase to be significantly refined and uniformly distributed. In addition, nanosilicon particles with a grain size of 30~100 nm were formed after HCPEB treatment, as shown by TEM observation. XRD results indicate that Si diffraction peaks broadened after HCPEB treatment. The microhardness tests demonstrate that the microhardness at the midpoint from the halo edge to center decreased sharply from 9770.7 MPa at 5 pulses to 2664.14 MPa at 25 pulses. The relative wear resistance of a 15-pulse sample is effectively improved by a factor of 6.5, exhibiting optimal wear resistance.

scholarly journals Study on microstructure and wear resistance of Zr-17Nb alloy irradiated by high current pulsed electron beam

2020 ◽  
Vol 59 (1) ◽  
pp. 514-522
Author(s):  
Yue Sun ◽  
Kui Li ◽  
Bo Gao ◽  
Pengyue Sun ◽  
Haiyang Fu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Electron Beam ◽  
Xrd Analysis ◽  
Pulse Number ◽  
Alloy Surface ◽  
Metallographic Analysis ◽  
Test Results ◽  
High Current ◽  
X Ray Diffraction ◽  
Pulsed Electron Beam

AbstractIn this paper, the microstructure and wear resistance of Zr-17Nb alloy treated by high current pulsed electron beam were studied in detail. A phase change occurs after pulse treatments using X-Ray Diffraction (XRD) analysis, showing β (Nb) phase and α (Zr) phase transformed by a part of β (Zr, Nb) phase. Also, narrowing and shifting of β (Zr, Nb) diffraction peaks were found. Scanning Electron Microscope (SEM) and metallographic analysis results reveal that the microstructure of alloy surface before high current pulsed electron beam (HCPEB) treatment is composed of equiaxed crystals. But, after 15 and 30 pulse treatments, crater structures are significantly reduced. Besides, it was also found that the alloy surface has undergone eutectoid transformation after 30 pulse treatments, and the reaction of β (Zr, Nb) → αZr + βNb had occurred. Microhardness test results show that microhardness value presents a downward trend as the number of pulses increases, which is mainly due to the coarsening of the grains and the formation of a softer β (Nb) phase after phase transformation. The wear resistance test results show that the friction coefficient increases first, then decreases and then increases with the increase of pulse number.

Influence of High Current Pulsed Electron Beam (HCPEB) Treatment on Wear Resistance of Hypereutectic Al-17.5Si and Al-20Si Alloys

2011 ◽  
Vol 675-677 ◽  
pp. 693-696 ◽  
Author(s):  
Y. Hao ◽  
Bo Gao ◽  
Gan Feng Tu ◽  
Z. Wang ◽  
Sheng Zhi Hao
Keyword(s):  
Wear Resistance ◽  
Surface Layer ◽  
Electron Beam ◽  
Supersaturated Solid Solution ◽  
High Current ◽  
Pulsed Electron Beam ◽  
Primary Si ◽  
Modified Surface ◽  
Positive Effect ◽  
Modified Surface Layer

The paper reports an analysis of the effect of high current pulsed electron beam(HCPEB) on microstructure transformations and wear resistance of hypereutectic Al-Si alloys. HCPEB treatment with 2.5 J /cm2 energy density leads to the formation of “halo” centered on primary Si, composition homogeneity, the formation of supersaturated solid solution of Al and grain refinement of top melted surface layer. The wear resistance of 15 pulse-treated Al-17.5Si and Al-20Si alloys is drastically improved by a factor of 6.5 and 2, respectively. The increase of hardness in modified surface layer has a positive effect on wear of hypereutectic Al-Si alloys.

The effect of neodymium on the microcracks generated on the Al–17.5Si alloy surface treated by high current pulsed electron beam

2016 ◽  
Vol 364 ◽  
pp. 490-497 ◽  
Author(s):  
Liang Hu ◽  
Bo Gao ◽  
Guanglin Zhu ◽  
Yi Hao ◽  
Shuchen Sun ◽  
...  
Keyword(s):  
Electron Beam ◽  
Alloy Surface ◽  
High Current ◽  
Pulsed Electron Beam

The metastable structure of hypereutectic Al–17·5Si alloy surface induced by high current pulsed electron beam

2015 ◽  
Vol 19 (sup5) ◽  
pp. S5-320-S5-324 ◽  
Author(s):  
L. Hu ◽  
B. Gao ◽  
J. K. Lv ◽  
Y. Hao ◽  
G. F. Tu ◽  
...  
Keyword(s):  
Electron Beam ◽  
Alloy Surface ◽  
High Current ◽  
Pulsed Electron Beam ◽  
Metastable Structure

The structure and properties of boron carbide ceramics modified by high-current pulsed electron-beam

2016 ◽  
Author(s):  
Yuri Ivanov ◽  
Oleg Tolkachev ◽  
Maria Petyukevich ◽  
Anton Teresov ◽  
Olga Ivanova ◽  
...  
Keyword(s):  
Electron Beam ◽  
Boron Carbide ◽  
Structure And Properties ◽  
High Current ◽  
Pulsed Electron Beam ◽  
Carbide Ceramics
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