Microstructure and thermal stability of bulk nanocrystalline alloys produced by surface mechanical attrition treatment

2014 ◽  
Vol 292 ◽  
pp. 556-562 ◽  
Author(s):  
Wenbo Liu ◽  
Chi Zhang ◽  
Zhigang Yang ◽  
Zhixin Xia
Keyword(s):  
Thermal Stability ◽  
Nanocrystalline Alloys ◽  
Surface Mechanical Attrition Treatment ◽  
Mechanical Attrition ◽  
Bulk Nanocrystalline ◽  
Thermal Stability Of

Thermal Stability of Nanocrystalline Ti6Al4V Produced by Surface Mechanical Attrition Treatment

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.

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

2007 ◽  
Vol 546-549 ◽  
pp. 1129-1134 ◽  
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.

Thermal Stability of Nanocrystalline BCC-Ti Formed by Phase Transformation During Surface Mechanical Attrition Treatment

NANO ◽  
2017 ◽  
Vol 12 (09) ◽  
pp. 1750113 ◽  
Author(s):  
Quantong Yao ◽  
Jian Sun ◽  
Guanglan Zhang ◽  
Weiping Tong ◽  
Hui Zhang
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Phase Transformation ◽  
Surface Layer ◽  
Annealing Treatment ◽  
Surface Mechanical Attrition Treatment ◽  
Excellent Thermal Stability ◽  
Mechanical Attrition ◽  
Average Grain Size ◽  
Thermal Stability Of

This paper reports the transformation of HCP-Ti into BCC-Ti in the Ti–6Al–4V alloy induced by surface mechanical attrition treatment (SMAT). The processes of surface nanocrystallization (SNC) and phase transformation were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the average grain size in the surface layer gradually decreased with increasing SMAT duration, but plateaued at 10[Formula: see text]nm after 90[Formula: see text]min of SMAT, while the proportion of BCC-Ti in the surface layer gradually increased. The refined grains displayed equiaxed grain morphology with a random crystallographic orientation. The thermal stability of nanocrystalline BCC-Ti was investigated by subjecting it to isothermal annealing treatment in the temperature range of 450–800[Formula: see text]C. BCC-Ti nanocrystallites were shown to exhibit excellent thermal stability up to 650[Formula: see text]C, whereas those in HCP-Ti started to recrystallize at approximately 550[Formula: see text]C.

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