Microstructures and Phase Transformations of Ti-50.9at%Ni Alloy Processed by Equal Channel Angular Extrusion at Medium Temperature

2007 ◽  
pp. 877-880
Author(s):  
Chao Ying Xie ◽  
Zhi Guo Fan
Keyword(s):  
Phase Transformations ◽  
Equal Channel Angular Extrusion ◽  
Medium Temperature ◽  
Ni Alloy ◽  
Angular Extrusion

Microstructures and Phase Transformations of Ti-50.9at%Ni Alloy Processed by Equal Channel Angular Extrusion at Medium Temperature

2007 ◽  
Vol 561-565 ◽  
pp. 877-880 ◽  
Author(s):  
Chao Ying Xie ◽  
Zhi Guo Fan
Keyword(s):  
Phase Transformation ◽  
Phase Transformations ◽  
Equal Channel Angular Extrusion ◽  
Martensitic Transformations ◽  
Optical Microscope ◽  
Medium Temperature ◽  
Thermal Peak ◽  
Ni Alloy ◽  
Coarse Grains ◽  
Angular Extrusion

Submicron-grained Ti-50.9at%Ni alloy was prepared by Equal Channel Angular Extrusion (ECAE) at medium temperature(500°C). Microstructure evolution and phase transformations of Ti-50.9at%Ni alloy after ECAE processes at medium temperature have been investigated by optical microscope, TEM and DSC tests. It is found that the initial coarse grains of Ti-50.9at%Ni alloy were refined into submicron grains, smaller than 0.5 um in size, after eight passes ECAE at 500°C. Martensitic transformation temperatures decreased remarkably after one pass ECAE and more gently with increasing the pass number of ECAE. R phase transformation was stimulated after ECAE processes and underwent within a larger temperature range with an ambiguous thermal peak. The reverse R phase and reverse martensitic transformations, during heating, were separated eventually after eight passes ECAE.

Recrystallization Characteristics of Ti-50.9at%Ni Alloy Processed by Equal Channel Angular Extrusion

2007 ◽  
Vol 26-28 ◽  
pp. 385-388 ◽  
Author(s):  
Zhi Guo Fan ◽  
Chao Ying Xie
Keyword(s):  
High Temperature ◽  
Optical Microscopy ◽  
Equal Channel Angular Extrusion ◽  
Recrystallization Process ◽  
Recrystallization Behavior ◽  
Ni Alloy ◽  
Coarse Grains ◽  
Angular Extrusion

The initial coarse grains of Ti-50.9at%Ni alloy were refined into submicron grains, small than 0.5 um in size, after eight passes Equal Channel Angular Extrusion (ECAE) at 500°C. Optical microscopy and high temperature DSC tests were applied to investigate recrystallization behavior. It is found that the recrystallization start (Rs) and recrystallization peak (Rp) temperatures of Ti-50.9at%Ni specimens processed by eight passes ECAE are lower than that of the samples processed by one pass ECAE. Ti-50.9at%Ni specimens processed by eight passes ECAE with submicron grains are characterized by higher stability and need less energy to finish recrystallization process.

Phase Transformations and Super-Elasticity of a Ni-Rich TiNi Alloy with Ultrafine-Grained Structure

2010 ◽  
Vol 667-669 ◽  
pp. 1137-1142 ◽  
Author(s):  
Zhi Guo Fan ◽  
Jie Song ◽  
Xiao Ning Zhang ◽  
Chao Ying Xie
Keyword(s):  
Phase Transformations ◽  
Equal Channel Angular Extrusion ◽  
Martensitic Transformations ◽  
Tini Alloy ◽  
Solution Treated ◽  
Ultrafine Grained ◽  
Treated Sample ◽  
Ni Alloy ◽  
Loading And Unloading ◽  
Elasticity Characteristics

A Ni-rich Ti-50.7.at%Ni alloy was processed by Equal Channel Angular Extrusion (ECAE) at 500°C. After 8 passes ECAE, microstructure was refined to sub-micron scale, approximately 0.2 μm～0.3 μm. TEM observation reveals that Ti3Ni4 phase precipitated in Ni-rich Ti-50.7.at%Ni alloy during the preheating treatment before each ECAE pass, but re-dissolved during sequent ECAE processes. After ECAE treatment, the B2R transformation occurred within a larger temperature range. Comparing with the solution-treated TiNi specimen, the martensitic transformations start (Ms) and peak temperatures (Mp) of TiNi specimens ECAEed were dramatically lowered. Super-elasticity characteristics of TiNi alloy were tested by tensile loading and unloading cycles. The results reveal that at a tensile strain of 4% or smaller, ultrafine-grained (UFG) TiNi alloy processed by 4 passes ECAE shows better super-elasticity than solution-treated sample. Microstructure evolution and its effect on phase transformations and super-elasticity characteristics have been discussed.

Analysis of texture evolution in equal channel angular extrusion of copper using a new flow field

2004 ◽  
Vol 52 (7) ◽  
pp. 1885-1898 ◽  
Author(s):  
László S. Tóth ◽  
Roxane Arruffat Massion ◽  
Lionel Germain ◽  
Seung C. Baik ◽  
Satyam Suwas
Keyword(s):  
Flow Field ◽  
Equal Channel Angular Extrusion ◽  
Texture Evolution ◽  
Angular Extrusion

Tube Equal Channel Angular Extrusion (tECAE) of Mg-3Al-1Zn alloy

2021 ◽  
pp. 141236
Author(s):  
Abhinav Srivastava ◽  
Matthew W. Vaughan ◽  
Bilal Mansoor ◽  
Wahaz Nasim ◽  
Robert Barber ◽  
...  
Keyword(s):  
Equal Channel Angular Extrusion ◽  
Angular Extrusion

Shear induced simultaneous consolidation and alignment of silicon nanowires into ingots using equal channel angular extrusion (ECAE)

2015 ◽  
Vol 2 (1) ◽  
pp. 015013 ◽  
Author(s):  
Venkata Vasiraju ◽  
Lance Brockway ◽  
Shreyas Balachandran ◽  
Arun Srinivasa ◽  
Sreeram Vaddiraju
Keyword(s):  
Silicon Nanowires ◽  
Equal Channel Angular Extrusion ◽  
Angular Extrusion

Mechanical Properties of Equal-Channel Angular Extrusion-Processed Al-20Zn Alloy

2012 ◽  
Vol 445 ◽  
pp. 195-200
Author(s):  
Murat Aydin ◽  
Yakup Heyal
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Equal Channel Angular Extrusion ◽  
Considerable Change ◽  
Fatigue Properties ◽  
Dendritic Microstructure ◽  
Two Phase ◽  
Angular Extrusion ◽  
Alloy Increase ◽  
The Impact

The mechanical properties mainly tensile properties, impact toughness and high-cycle fatigue properties, of two-phase Al-20Zn alloy subjected to severe plastic deformation (SPD) via equal-channel angular extrusion (ECAE) using route A up to 2 passes were studied. The ECAE almost completely eliminated as-cast dendritic microstructure including casting defects such as micro porosities. A refined microstructure consisting of elongated micro constituents, α and α+η eutectic phases, formed after ECAE via route A. As a result of this microstructural change, mechanical properties mainly the impact toughness and fatigue performance of the as-cast Al-20Zn alloy increased significantly through the ECAE. The rates of increase in fatigue endurance limit are approximately 74 % after one pass and 89 % after two passes while the increase in impact toughness is 122 %. Also the yield and tensile strengths of the alloy increase with ECAE. However, no considerable change occurred in hardness and percentage elongation of the alloy. It was also observed that the ECAE changed the nature of the fatigue fracture characteristics of the as-cast Al-20Zn alloy.

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