Contribution of Twins to the Strengthening of Commercial Purity Titanium after Equal-Channel Angular Pressing

2010 ◽  
Vol 667-669 ◽  
pp. 719-724 ◽  
Author(s):  
Yue Zhang ◽  
Saleh N. Alhajeri ◽  
Roberto B. Figueiredo ◽  
Nong Gao ◽  
Jing Tao Wang ◽  
...  
Keyword(s):  
Yield Strength ◽  
Equal Channel Angular Pressing ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Commercial Purity ◽  
Angular Pressing ◽  
Commercial Purity Titanium ◽  
Elongation To Failure ◽  
Mechanical Twins ◽  
Purity Titanium

Room temperature equal-channel angular pressing (ECAP) was employed on commercial purity titanium in the present work. Mechanical twining was observed in ~90% grains while the grains were not significantly refined (~10 μm) after ECAP. TEM observations showed that the twins observed under OM are usually composed of a serial of parallel twin bands with a width of ~1 μm. Microhardness and tensile tests showed that such a coarse-grained microstructure combined with a high fraction of mechanical twins has a microhardness of ~ 240 Hv, yield strength of ~ 730 MPa, tensile strength of ~ 740 MPa and elongation to failure of ~ 16%. This yield strength is much higher than 620-640 MPa, the yield strength of ultrafine-grained titanium by 8~12 passes of ECAP at 450 oC with a grain size of 200-300 nm, and is close to ~ 790 MPa, the yield strength of commercial Ti-6Al-4V alloys.

scholarly journals Commercial Purity Titanium Processed by Rotary-Die Equal Channel Angular Pressing Method

2005 ◽  
Vol 46 (9) ◽  
pp. 2098-2101 ◽  
Author(s):  
Akira Watazu ◽  
Ichinori Shigematsu ◽  
Aibin Ma ◽  
Kazutaka Suzuki ◽  
Tsunemichi Imai ◽  
...  
Keyword(s):  
Equal Channel Angular Pressing ◽  
Commercial Purity ◽  
Pressing Method ◽  
Angular Pressing ◽  
Commercial Purity Titanium ◽  
Purity Titanium

scholarly journals Mechanical Properties and Microstructure of a Duplex Nanostructure

2010 ◽  
Vol 667-669 ◽  
pp. 973-978
Author(s):  
L. Chen ◽  
Ping Jiang ◽  
Xiao Lei Wu ◽  
Mu Xin Yang ◽  
Chang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Yield Strength ◽  
Uniform Elongation ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Uniaxial Tensile ◽  
Plastic Behavior ◽  
Angular Pressing ◽  
Elongation To Failure

The nanostructure was obtained in a duplex stainless steel (DSS) by means of equal channel angular pressing. The mechanical properties were characterized by uniaxial tensile tests, while the microstructure was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was shown that the yield strength in a deformed nanostructure increased significantly from 402 MPa to 1461 MPa as compared to its coarse-grained counterpart. In contrast, the uniform elongation decreased significant to only 2% together with elongation to failure of 9.8%, much lower than those of 25.4% and 42.6%. After annealing at 700°C for 10 minute, however, uniform elongation increases to 5.3% with the yield strength of 1200 MPa. TEM observation exhibited that deformation twins prevail in the austenite phase whereas the dislocations of high density present in ferrite. The plastic behavior in both phases was analyzed based on the deformation twinning and the presence of dislocation. Finally, the effect of the microstructure on mechanical properties was discussed.

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