Thermal Stability of Nanocrystalline AZ31 Magnesium Alloy Fabricated by Surface Mechanical Attrition Treatment

A nanostructured surface layer was produced on commercially AZ31 magnesium alloy using surface mechanical attrition treatment (SMAT). The microstructure evolution and deformation feature along the depth of the treated surface layer were characterized by transmission electron microscope (TEM) investigations. The grain refinement process, accompanied by an increase in the surface layer, involves: the onset of twins; the formation of microbands associated with the dislocation slipping; the subdivision of microbands into low angle grains and then highly disoriented polygonal submicronic grains, and further breakdown into randomly oriented nanograins with progression of dynamic recrystallization.

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Thermal Stability of Nanocrystalline Ti6Al4V Produced by Surface Mechanical Attrition Treatment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.898.41 ◽

2017 ◽

Vol 898 ◽

pp. 41-46

Author(s):

Quan Tong Yao ◽

Meng Nan Xing ◽

Guang Lan Zhang ◽

Wei Ping Tong

Keyword(s):

Electron Microscopy ◽

Thermal Stability ◽

Pure Titanium ◽

Surface Mechanical Attrition Treatment ◽

X Ray ◽

Transmission Electron ◽

Mechanical Attrition ◽

Nanocrystalline Layer ◽

Thermal Stability Of ◽

Scanning Electron

A pollution-free nanocrystalline layer was prepared on the surface of Ti6Al4V by surface mechanical attrition treatment (SMAT). The nanocrystalline samples were vacuum annealed at various temperatures and for different periods of time. The microstructure and thermal stability were characterized by X-ray (XRD), scanning electron microscopy (SEM) and, transmission electron microscopy (TEM). The results showed that the nanocrystalline Ti6Al4V presented a satisfactory thermal stability with the annealed temperature below 650°C. The critical growth temperature for nanocrystalline Ti6Al4V is 100°C higher than that for pure titanium.

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Thermal Stability of Nanocrystallized Surface Layer in Al-Zn-Mg Alloy by Surface Mechanical Attrition Treatment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.546-549.1129 ◽

2007 ◽

Vol 546-549 ◽

pp. 1129-1134 ◽

Cited By ~ 1

Author(s):

Jin Fang Ma ◽

Lan Qing Hu ◽

Xu Guang Liu ◽

Bing She Xu

Keyword(s):

Thermal Stability ◽

Grain Size ◽

Surface Layer ◽

Boundary Migration ◽

Mg Alloy ◽

Surface Mechanical Attrition Treatment ◽

Mechanical Attrition ◽

Nanostructured Layer ◽

Average Grain Size ◽

Thermal Stability Of

After surface mechanical attrition treatment (SMAT) for Al-Zn-Mg alloy, a gradient structure with average grain size increased from 20nm in surface layer to about 100nm at a depth of 20μm was formed. The thermal stability of surface nanostructured layer in Al-Zn-Mg alloy samples was investigated by vacuum annealing at 100°C, 150°C, 200°C and 250°C for 1h, respectively. The microstructural evolution as well as the microhardness along the depth from top surface layer to matrix of SMATed samples was analyzed. Experimental results showed that the grain size of surface nanocrystallites remains in submicro-scale, ranging from 300nm to 400nm, when annealed at a temperature of 250°C, and the microhardness of surface nanostructured layer was still high compared with that of matrix, indicating satisfying thermal stability of nanocrystallized layer. This might be attributed to the presence of substantive trident grain boundaries and pinning effect of dispersive precipitated phases in nanocrystalline materials, which hindered the grain boundary migration that leading to grain growth.

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