Preperation of Ceramic Coatings on Ti Alloy by Surface Nanocrystallization/Micro-Arc Oxidation

2010 ◽  
Vol 146-147 ◽  
pp. 1821-1824
Author(s):  
Jin Xue Zhang ◽  
Guo Dong Hao

Nanostructured surface layer was produced on Ti-6Al-4V alloy by surface mechanical attrition treatment(SMAT) technique, and the composite ceramic coatings of surface nanocrystallization/micro-arc oxidation(SNC/MAO) were prepared on the nanocrystallized surface of Ti-6Al-4V alloy by pulsed single-polar micro-arc oxidation in NaAlO2 solution. XRD, SEM and TEM techniques were used to investigate the phase and surface morphology of ceramic coatings and the influences on the surface state of the alloys. Meantime, the mechanical properties of Ti alloys were measured by tensile test. The results show that after the SMAT treatment for a short period of time, the surface layer was refined into ultrafine grains. The influences of the SMAT technique on the surface morphology of the ceramic coatings were also studied. The ceramic coatings are mainly composed of Al2TiO5, more compact and less porous than those untreated. The mechanical properties of Ti-6Al-4V alloy by SMAT technique are improved, compared with those untreated by SMAT technique.

2010 ◽  
Vol 105-106 ◽  
pp. 67-69 ◽  
Author(s):  
Guo Dong Hao ◽  
Yong Liang Guo ◽  
Gang Liu ◽  
Xin Mei Zhang

Nanostructured surface layer was produced on Ti-6Al-4V alloy by surface mechanical attrition treatment (SMAT) technique, and the composite ceramic coatings of surface nanocrystallization/ micro-arc oxidation (SNC/MAO) were prepared on the nanocrystallized surface of Ti-6Al-4V alloy by pulsed single-polar micro-arc oxidation in NaAlO2 solution. XRD, SEM and TEM techniques were used to investigate the phase and surface morphology of ceramic coatings and the influences on the surface state of the alloys. Meantime, the mechanical properties of Ti alloys were measured by tensile test. The results show that after the SMAT treatment for a short period of time, the surface layer was refined into ultrafine grains. The influences of the SMAT technique on the surface morphology of the ceramic coatings were also studied. The ceramic coatings are mainly composed of Al2TiO5, more compact and less porous than those untreated. The mechanical properties of Ti-6Al-4V alloy by SMAT technique are improved, compared with those untreated by SMAT technique.


2008 ◽  
Vol 368-372 ◽  
pp. 1322-1324 ◽  
Author(s):  
Guo Dong Hao ◽  
Yong Liang Guo ◽  
Xin Mei Zhang ◽  
Gang Liu ◽  
Zhao Hua Jiang

Nanostructured surface layer was produced on the Ti-6Al-4V alloy by surface mechanical attrition treatment (SMAT) technique, and then the ceramic composite coatings of surface nanocrystallization/ micro-arc oxidation (SNC/MAO) were prepared on the nanocrystallized surface of Ti-6Al-4V alloy by pulsed single-polar micro-arc oxidation in NaAlO2 solution. The phase composition, morphology of surface and section and element content of the nanostructured surface layer and the ceramic coatings were investigated by XRD, TEM, SEM and EDS, respectively. The results showed that after the SMAT technique treatment for a short period of time, the surface layer was refined into ultrafine grains. The thickness of the coatings on the substrate treated by SMAT technique is about 10μm by micro-arc oxidation, which is thicker than the ones on the substrate untreated by SMAT technique, and the ceramic coatings are mainly composed of Al2TiO5. Besides, a bright interface layer comes out between the substrate and the coating when the substrate treated by SMAT technique. The influences of the SMAT technique on the surface morphology of the ceramic coatings also changed. The coatings using the SMAT technique were more compact and less porous than the ones on the substrate untreated by SMAT technique. The content of elements in the nanostructured surface layer on Ti-6Al-4V alloy had changed after the SMAT technique: the content of Ti increased, the content of V decreased, and the content of Al changed a little. The contents of Al and P in the coating increased while the content of Ti decreased.


2007 ◽  
Vol 353-358 ◽  
pp. 1810-1813 ◽  
Author(s):  
Xiao Hua Yang ◽  
Wei Zhen Dui ◽  
Gang Liu

The mechanical properties of the 316L stainless steel subjected to surface mechanical attrition treatment (SMAT) have been studied, these properties are hardness, tensile properties and wear resistance. The research shows that the thickness of the hardened layer increases with the increasing of the treating time. The refined microstructure in the treated layer led to increasing in hardness, strength, and wear resistance. It is obvious that the surface layer hardness and bulk yield strength are increasing when the SMAT time reaches 5 minutes. The increase of surface layer wear resistance is obvious when the SMAT time is 15 minutes. The SEM observation of the wear scars shows that the nanocrystalline layer might reduce the effect of adhesive wear of 316L stainless steel. Therefore, the wear mechanism changes from adhesive abrasion to grinding particle abrasion after SMAT.


2009 ◽  
Vol 614 ◽  
pp. 189-196
Author(s):  
H.L. Chan ◽  
Jian Lu

Different Power types and parameters in the electrodeposition process result in different microstructures and hence mechanical properties. In this paper, direct current and double pulse power with different combinations of on and off time have been used for electrodeposition. The tensile properties of the electrodeposited (Ed) Cu with different parameters in process have been studied and also the microstructures of the Cu obtained have been examined by SEM. This paper aims at explaining the effects of one of the important parameters in electrodeposition: different power types on the tensile properties. The tensile properties of Ed Cu after Surface Mechanical Attrition Treatment (SMAT) are also shown in this paper.


Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 94
Author(s):  
Yuqing Chen ◽  
Guofeng Wang ◽  
Yongkang Liu ◽  
Liqiang Zhan ◽  
He Diao ◽  
...  

Titanium alloys used to be welded to gain good joint strength at 920 °C through diffusion bonding. However, due to the heat preservation at high temperatures for a long time, we obtain joints with great bond strength while the mechanical properties of the sheet are lost. In this paper, taking Ti6Al4V alloy as an example, we studied the microstructure of the surface under the different times of surface mechanical attrition treatment (SMAT). In addition, the microstructure and mechanical properties after diffusion bonding at 800 °C-5 MPa-1 h were also conducted. The results show that the shear strength of TC4 alloy welded joint after SMAT treatment is improved, and the maximum shear strength can reach 797.7 MPa, up about 32.4%


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