Microstructure Appearance of TC4 Titanium Alloy Welded Join by Pulsed Electron Beam

2020 ◽  
Vol 982 ◽  
pp. 143-150
Author(s):  
Hai Lin Dai ◽  
Rui Zhao Du ◽  
Yun He ◽  
Shuai Xing ◽  
Fang Jun Liu
Keyword(s):  
Grain Size ◽  
Titanium Alloy ◽  
Electron Beam ◽  
Weld Metal ◽  
Pulsed Electron Beam ◽  
Tc4 Titanium Alloy ◽  
Β Phase ◽  
Α Phase ◽  
Fast Cooling ◽  
Cooling Velocity

Study on microstructure appearance of 3 mm thick TC4 titanium alloy welded join by common electron beam and pulsed electron beam were carried out. Experimental results show that pulsed electron beam improved grain size and decreased the cooling velocity of weld metal by oscillation and fast cooling effect, the acicular martensite decomposes β phase and transforms to finer and more α′ phase, which shows an interwoven pattern.

Influence of Hydrogen on Microstructure of Electron Beam Welded Joint

2013 ◽  
Vol 753-755 ◽  
pp. 367-371
Author(s):  
Xin Liu ◽  
Zhi Yong Mao
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Weld Metal ◽  
Hydrogen Content ◽  
Welded Joints ◽  
Welded Joint ◽  
Optical Microscope ◽  
Hydrogen Charging ◽  
Tc4 Titanium Alloy ◽  
Oxygen Analyzer

Hydrogen distributions of TC4 electron beam welded joints with different hydrogen contents were measured by hydrogen oxygen analyzer. Microstructures of electron beam welded joints for TC4 titanium alloy with different hydrogen contents were observed and analyzed by optical microscope and TEM. And the influence of hydrogen on microstructure of the joints was investigated. The results show that the hydrogen content of weld HAZ is higher than other zones in the electron beam welded joints, while the hydrogen content of fusion zone is lower than other zones in the electron beam welded joints. The microstructure of the weld metal is fine lamellar α + β phase after hydrogen charging. In the range of hydrogen contents discussed in this study (from 0 to 0.101 wt. %), with the increase of hydrogen content, there is little change in the appearance of the microstructure of the weld metal. There are stacking fault and dislocation in the microstructure of TC4 electron beam welded joints with different hydrogen contents after hydrogen charging. The presence of hydrogen can promote the formation of twins in electron beam welded joints. With the increase of hydrogen content, the number of twins is increased.

Effect of Hydrogen on Microstructure of TA15 Electron Beam Welded Joint

2011 ◽  
Vol 287-290 ◽  
pp. 2393-2396 ◽  
Author(s):  
Xin Liu ◽  
Zhi Yong Mao ◽  
Yong Ping Lei
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Weld Metal ◽  
Hydrogen Content ◽  
Welded Joints ◽  
Welded Joint ◽  
Hydrogen Charging ◽  
Β Phase ◽  
Ta15 Titanium Alloy ◽  
Certainty Level

Microstructures of electron beam welded joints for TA15 titanium alloy with different hydrogen contents were observed and analyzed by SEM and TEM. And the influence of hydrogen on microstructure of the joints was investigated. The results show that the microstructure of the weld metal is lamellar α+β phase after hydrogen charging. In the range of hydrogen contents discussed in this study (from 0 to 0.101 wt%), With the increase of hydrogen content, there is little change in the appearance of the microstructure of the weld metal. The presence of hydrogen can promote the growth of twins in electron beam welded joints. With the increase of hydrogen content, the number of twins is increased. When hydrogen content reaches to a certainty level, hydrides are found in TA15 electron beam welded joints.

scholarly journals Material Characterisation and Computational Thermal Modelling of Electron Beam Powder Bed Fusion Additive Manufacturing of Ti2448 Titanium Alloy

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7359
Author(s):  
Qiushuang Wang ◽  
Wenyou Zhang ◽  
Shujun Li ◽  
Mingming Tong ◽  
Wentao Hou ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Thermal History ◽  
Computational Modelling ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
Material Microstructure ◽  
Powder Bed ◽  
Β Phase ◽  
Α Phase

Ti-24Nb-4Zr-8Sn (Ti2448) is a metastable b-type titanium alloy developed for biomedical applications. In this work, cylindrical samples of Ti2448 alloy have been successfully manufactured by using the electron beam powder bed fusion (PBF-EB) technique. The thermal history and microstructure of manufactured samples are characterised using computational and experimental methods. To analyse the influence of thermal history on the microstructure of materials, the thermal process of PBF-EB has been computationally predicted using the layer-by-layer modelling method. The microstructure of the Ti2448 alloy mainly includes β phase and a small amount of α” phase. By comparing the experimental results of material microstructure with the computational modelling results of material thermal history, it can be seen that aging time and aging temperature lead to the variation of α” phase content in manufactured samples. The computational modelling proves to be an effective tool that can help experimentalists to understand the influence of macroscopic processes on material microstructural evolution and hence potentially optimise the process parameters of PBF-EB to eliminate or otherwise modify such microstructural gradients.

Grain Size Effect on Mechanical Properties of Titanium Alloy

2014 ◽  
Vol 626 ◽  
pp. 548-552 ◽  
Author(s):  
Cho-Pei Jiang ◽  
Zong Han Huang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Titanium Alloy ◽  
Size Effect ◽  
Annealing Temperature ◽  
Grain Size Effect ◽  
Β Phase ◽  
Commercially Pure ◽  
Α Phase ◽  
Pure Grade

The aim of this study is to investigate the effect of grain size on mechanical properties of commercially pure grade 2 (CP2) titanium bar with a diameter of 5 mm. The results reveal that the microstructure of β-phase forms when the annealing temperature exceeds 800oC. The formation of β-phase leads to reduce the ductility but increase hardness. The strength coefficient, yielding stress and hardness decrease with increasing of grain size when the microstructure of specimen is the α-phase.

Influence of Isothermal Forging Temperature on Microstructure and Tensile Properties of Ti-5.8Al-4.0Sn-4.0Zr-0.7Nb-0.4Si-1.5Ta Near-α Titanium Alloy

2010 ◽  
Vol 97-101 ◽  
pp. 153-157
Author(s):  
Tao Wang ◽  
Hong Zhen Guo ◽  
Jian Hua Zhang ◽  
Ze Kun Yao
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Titanium Alloy ◽  
Tensile Properties ◽  
Room Temperature ◽  
Volume Fraction ◽  
Constant Strain Rate ◽  
Isothermal Forging ◽  
Α Phase ◽  
Transus Temperature

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.

Influences of Solution Temperatures on Microstructure and Mechanical Properties of near α Titanium Alloy

2021 ◽  
Vol 1035 ◽  
pp. 89-95
Author(s):  
Chao Tan ◽  
Zi Yong Chen ◽  
Zhi Lei Xiang ◽  
Xiao Zhao Ma ◽  
Zi An Yang
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
High Temperature ◽  
Room Temperature ◽  
Solution Temperature ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Β Phase ◽  
Α Phase ◽  
New Type

A new type of Ti-Al-Sn-Zr-Mo-Si series high temperature titanium alloy was prepared by a water-cooled copper crucible vacuum induction melting method, and its phase transition point was determined by differential thermal analysis to be Tβ = 1017 °C. The influences of solution temperature on the microstructures and mechanical properties of the as-forged high temperature titanium alloy were studied. XRD results illustrated that the phase composition of the alloy after different heat treatments was mainly α phase and β phase. The microstructures showed that with the increase of the solution temperature, the content of the primary α phase gradually reduced, the β transformation structure increased by degrees, then, the number and size of secondary α phase increased obviously. The tensile results at room temperature (RT) illustrated that as the solution temperature increased, the strength of the alloy gradually increased, and the plasticity decreased slightly. The results of tensile test at 650 °C illustrated that the strength of the alloy enhanced with the increase of solution temperature, the plasticity decreased first and then increased, when the solution temperature increased to 1000 °C, the alloy had the best comprehensive mechanical properties, the tensile strength reached 714.01 MPa and the elongation was 8.48 %. Based on the room temperature and high temperature properties of the alloy, the best heat treatment process is finally determined as: 1000 °C/1 h/AC+650 °C/6 h/AC.

Microstructure Evolution of near α Titanium Alloy during Multi-Step Thermomechanical Deformation Process

2021 ◽  
Vol 1035 ◽  
pp. 305-311
Author(s):  
Qing Shan Liu ◽  
Bo Long Li ◽  
Tong Bo Wang ◽  
Cong Cong Wang ◽  
Peng Qi ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Strain Curve ◽  
Optical Microscope ◽  
Phase Content ◽  
Β Phase ◽  
Α Phase ◽  
Gleeble 3500

A new type of near α high temperature titanium alloy of Ti-Al-Sn-Zr-Mo-Si-Er was studied. The samples with different primary α phase content were prepared by solid solution at 950 °C/1 h—1010 °C/1 h. The multi-step hot compression experiments were carried out by Gleeble-3500 in a sequence of upper region of α + β phase, then followed by lower region of α + β phase. The effects of primary α phase content and deformation temperature on the microstructure of the alloy were studied by means of true stress-strain curve and optical microscope. The results show that the content of primary α phase gradually decreases from 45.4% at 950°C to 0% at 1010°C. As the deformation temperature decreases from 940°C to 900°C, the content of α phase increases gradually from 65% to 94%, which is changed from dynamic recrystallization to deformed structure elongated along RD direction. It is found that the arrangement of α phase along RD direction is the longest at 920°C. With the increase of the deformation temperature in the multi-step high temperature region from 970°C to 990°C, the width of deformed α phase decreases from 3.64 μm at 970°C to 2.71 μm at 990°C. The optimized microstructure is composed of 20% primary α phase arranged along RD direction. This process has a certain potential in the process of hot deformation of the alloy. Key words: high temperature titanium alloy, primary α phase, multi-step hot deformation

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