Influence of High Magnetic Field on β-a Phase Transformation in TC4 Titanium Alloy

2014 ◽  
Vol 941-944 ◽  
pp. 112-115
Author(s):  
Hong Ming Wang ◽  
Guirong Li ◽  
Yue Ming Li ◽  
Yu Hua Cui ◽  
Cong Xiang Peng ◽  
...  

In the TC4 titanium alloy subject to high pulsed magnetic field, the phase transformation from α to β occurs. When the magnetic induced intensity increased from 2T, 3T to 4T with constant 30 pulses, the percent of α phase adds up gradually. When the magnetic induced intensity is 4T the volume fraction of α phase amounts up to 59%. It is ascertained that magnetic field has taken a positive influence on the phase transformation because of the variation of inner energy induced by magnetic field.

2020 ◽  
Vol 321 ◽  
pp. 11048
Author(s):  
Ren Yong ◽  
Yang Nan ◽  
Lei Jinwen ◽  
Li Shaoqiang ◽  
Du Yuxuan

The effects of primary α phase volume fraction on the tensile properties at 400℃ of TC4 titanium alloy was studied by different solution temperature(Tβ-(10~80)℃). The effects of the thick of secondary α phase on the tensile properties at 400℃ of TC4 titanium alloy was studied by different cooling speed after solution treatment (water quench, air cooling, furnace cooling). The results show that with the decrease of primary α phase, the tensile and yield strength increase up, but the ductility has a little change. The thick of secondary α phase increases with the deceases of cooling speed after solution treatment, highest tensile and yield strength by water quench, the tensile strength of air cooling and furnace cooling were basically the same, but the yield strength of furnace cooling was 40MPa lower than air cooling. Therefore, the influence of the primary α phase volume fraction on the tensile strength at 400℃ was particularly obvious, we can control solution treatment and cooling way in combination with different requirements.


2010 ◽  
Vol 97-101 ◽  
pp. 153-157
Author(s):  
Tao Wang ◽  
Hong Zhen Guo ◽  
Jian Hua Zhang ◽  
Ze Kun Yao

The microstructures and room temperature and 600°C tensile properties of Ti-5.8Al-4.0Sn-4.0Zr-0.7Nb -0.4Si-1.5Ta alloy after isothermal forging have been studied. The forging temperature range was from 850°C to 1075°C, and the constant strain rate of 8×10-3/S-1 was adopted. With the increase of forging temperature, the volume fraction of primary α phase decreased and the lamellar α phase became thicker when the temperatures were in range of 850°C -1040°C; The grain size became uneven and the α phase had different forms when the forging temperature was 1040°C and 1075°C respectively; The tensile strength was not sensitive to the temperature and the most difference was within 20MPa. Tensile strength and yield strength attained to the maximum when temperature was 1020°C; the ductility decreased with the increase of forging temperature, and this trend became more obvious if forging temperature was above the β-transus temperature.


Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 544 ◽  
Author(s):  
Xueqi Jiang ◽  
Xiaoqiang Shi ◽  
Xiaoguang Fan ◽  
Qi Li

Large size (>10000 μm2) precipitate-free zones in the absence of microsegregation were observed in the near-β Ti-55531 titanium alloy after furnace cooling from high temperature and longtime annealing in the single-β phase field. To reveal the formation mechanism of the large size precipitate-free zone, continuous cooling and isothermal heat treatment were carried out to investigate the β-α phase transformation process. It was found that the large size precipitate free zone is attributed to the heterogeneous nucleation of α phase. The nucleation site evolves in three different modes: I-random nucleation inside the β grain, II-network nucleation inside the β grain and, III-heterogeneous nucleation on the precipitated α phase. Modes I and II lead to homogeneous transformed structure while Mode III results in the large size precipitate-free zone. Both modes II and III are promoted at high annealing temperature, rapid cooling above 600 °C or slow cooling below 600 °C. Mode II is common as it can minimize the strain energy in phase transformation. As a result, the formation of the large size precipitate-free zone is not deterministic.


2014 ◽  
Vol 1004-1005 ◽  
pp. 123-126 ◽  
Author(s):  
Jian Yin ◽  
Xiu Jun Ma ◽  
Jun Ping Yao ◽  
Zhi Jian Zhou

Effect of pulsed magnetic field treatment on the microstructure and mechanical properties of Mg97Y2Zn1 alloy has been investigated. When the pulsed magnetic field is applied on the alloy in semi-solid state, the α-Mg was modified from developed dendrite to fine rosette, resulting in a refined solidification microstructure with the grain size decreased from 4 mm to 0.5 mm. The volume fraction of the second phase ( X phase) increased by about 10 %. The yield strength, fracture strength and plasticity were improved by 21 MPa, 38 MPa and 2.4 %, respectively. The improvement of mechanical properties was attributed to the refined grain size and increased volume fraction of X phase.


2017 ◽  
Vol 36 (4) ◽  
pp. 373-379
Author(s):  
Congcong Zhao ◽  
Engang Wang ◽  
Xiaowei Zuo

AbstractHigh magnetic field (HMF) and solidification processes were changed during the solidification of both Cu-28 mass %Ag and Cu-72 mass %Ag alloys. The results indicated that the eutectic morphology in Cu-Ag alloys was affected by HMF, composition and solidification parameters. The lamellar spacing of Cu-28 mass %Ag alloy solidified by furnace-cooling was refined by the application of HMF owing to the decreased diffusion coefficient in mushy zone. The lamellar spacing in both Cu-28 mass %Ag sample held at the eutectic temperature and Cu-72 mass %Ag sample by slow controlling cooling was increased by HMF, which might be attributed to the dominated thermolectromagnetic convection. The lamellar spacing in Cu-72 mass %Ag alloys was increased compared with that of Cu-28 mass %Ag alloys because of the decreased growth rates. In Cu-28 mass %Ag alloy, however, fluid transverse velocity gradient was dominate rather than the growth rate and the imposition of HMF had reverse influences on the lamellar spacing. The lamellar-rod transition of Cu phase was promoted by HMF because of the increased Cu volume fraction in eutectic component. These results shed light on the dependence of eutectic morphology in Cu-Ag alloys on composition, external high magnetic field and solidification parameters.


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