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 ◽  
...  
2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
L. Hu ◽  
B. Gao ◽  
J. K. Lv ◽  
S. C. Sun ◽  
Y. Hao ◽  
...  

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.


2020 ◽  
Vol 59 (1) ◽  
pp. 514-522
Author(s):  
Yue Sun ◽  
Kui Li ◽  
Bo Gao ◽  
Pengyue Sun ◽  
Haiyang Fu ◽  
...  

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.


Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 61
Author(s):  
Liang Hu ◽  
Bo Gao ◽  
Ning Xu ◽  
Yue Sun ◽  
Ying Zhang ◽  
...  

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.


2015 ◽  
Vol 19 (sup5) ◽  
pp. S5-320-S5-324 ◽  
Author(s):  
L. Hu ◽  
B. Gao ◽  
J. K. Lv ◽  
Y. Hao ◽  
G. F. Tu ◽  
...  

2016 ◽  
Author(s):  
Yuri Ivanov ◽  
Oleg Tolkachev ◽  
Maria Petyukevich ◽  
Anton Teresov ◽  
Olga Ivanova ◽  
...  

2021 ◽  
Vol 11 (10) ◽  
pp. 4372
Author(s):  
Sergey G. Anikeev ◽  
Anastasiia V. Shabalina ◽  
Sergei A. Kulinich ◽  
Nadezhda V. Artyukhova ◽  
Daria R. Korsakova ◽  
...  

A new approach to fabricate TiNi surfaces combining the advantages of both monolithic and porous materials for implants is used in this work. New materials were obtained by depositing a porous TiNi powder onto monolithic TiNi plates followed by sintering at 1200 °C. Then, further modification of the material surface with a high-current-pulsed electron beam (HCPEB) was carried out. Three materials obtained (one after sintering and two after subsequent beam treatment by 30 pulses with different pulse energy) were studied by XRD, SEM, EDX, surface profilometry, and by means of electrochemical measurements, including OCP and EIS. Structural and compositional changes caused by HCPEB treatment were investigated. Surface properties of the samples during their storage in saline for 10 days were studied and a model experiment with cell growth (MCF-7) was carried out for the unmodified sample with an electron beam to detect cell appearance on different surface locations.


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