Effect of Container on the Microstructure and Properties of Powder Metallurgy TiAl Alloys

2015 ◽  
Vol 817 ◽  
pp. 604-609
Author(s):  
Jie Wu ◽  
Lei Xu ◽  
Zheng Guan Lu ◽  
Rui Peng Guo ◽  
Yu You Cui ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Mild Steel ◽  
Tial Alloy ◽  
Complex Shape ◽  
Pure Titanium ◽  
Tial Alloys ◽  
Microstructure And Properties ◽  
Commercial Pure Titanium ◽  
Near Net Shape ◽  
Cp Ti

Pre-alloyed powder of Ti-47Al-2Cr-2Nb-0.15B was prepared by a gas atomization process and powder metallurgy (PM) γ-TiAl alloys were made through a hot isostatic pressed (HIPed) route. The atomized powders were canned in containers, degassed, sealed, and HIPed. Effect of two different canning materials (mild steel and commercial pure titanium (CP-Ti)) on the microstructure and properties of as-HIPed γ-TiAl alloy were discussed. Due to the reaction between mild steel containers and γ-TiAl at relative high temperature (over 1230 °C), the γ-TiAl matrix is contaminated. CP-Ti canned γ-TiAl showed bigger yield and fracture strength than mild steel canned TiAl. PM γ-TiAl alloy parts having complex shape could be manufactured by the near net-shape process.

Preparation of Powder Metallurgy Ti-47Al-2Cr-2Nb-0.15B

2014 ◽  
Vol 552 ◽  
pp. 269-273 ◽  
Author(s):  
Jie Wu ◽  
Lei Xu ◽  
Yu You Cui ◽  
Rui Yang
Keyword(s):  
Powder Metallurgy ◽  
Mild Steel ◽  
Tial Alloy ◽  
Hot Isostatic Pressing ◽  
Gas Atomization ◽  
Alloyed Powder ◽  
Atomization Process ◽  
Tial Alloys ◽  
Cp Ti ◽  
Selection Of

Pre-alloyed powder of Ti-47Al-2Cr-2Nb-0.15B was prepared by a gas atomization process and powder metallurgy (PM) γ-TiAl alloys were made through a hot isostatic pressing route. The atomized powders were canned in mild steel and CP-Ti containers, degassed and sealed. The selection of mild steel and CP-Ti on the microstructure of HIPed γ-TiAl alloy was studied. Due to the reaction between mild steel containers and γ-TiAl at relative high temperature (over 1230oC), the γ-TiAl matrix is contaminated. Fully dense compact with CP-Ti container can be obtained by HIPing with suitable parameters of temperature.

Preparation and Properties of Ti-47Al-2Cr-2Nb-0.15B Alloy by Powder Metallurgy Route

2015 ◽  
Vol 817 ◽  
pp. 615-620 ◽  
Author(s):  
Zheng Guan Lu ◽  
Jie Wu ◽  
Lei Xu ◽  
Yu You Cui ◽  
Rui Yang
Keyword(s):  
Powder Metallurgy ◽  
Tial Alloy ◽  
Cast Alloy ◽  
Physical Adsorption ◽  
Hot Isostatic Pressing ◽  
Infrared Spectrometry ◽  
Gas Atomization ◽  
Adsorbed Gas ◽  
Near Net Shape ◽  
Adsorption Of Gases

Ti-47Al-2Cr-2Nb-0.15B alloy is a typical γ-TiAl alloy, and powder metallurgy (PM) as a near-net shape method was used to prepare it in this article. Clean pre-alloyed powders were prepared by argon gas atomization, and TiAl alloy was prepared by hot isostatic pressing (HIP) at 1150 °C and 1230 °C. However, surface contamination is inevitable due to chemical reactions with the residual O2 in the vacuum chamber during gas atomization, or due to physical adsorption of O2 and H2O during storage of the powder at room temperature. Infrared spectrometry was used to study this process. We found that the adsorption of gases is mainly H2O. The adsorbed gas in powders would deteriorate the performance of PM alloy, so a gas protection environment is suggested. Tensile properties of PM TiAl alloy were compared with as-cast alloy. Results showed that PM TiAl alloy had better strength which also had more fine and uniform microstructure.

scholarly journals Effect of Temperature and Dwell Time on Fatigue Crack Growth Behavior of CP-Ti

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1031 ◽  
Author(s):  
Chuan-Yi Su ◽  
Chang-Yu Zhou ◽  
Lei Lu ◽  
Jian Li ◽  
Peng-Yan Sun ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Dwell Time ◽  
Pure Titanium ◽  
Load Ratio ◽  
High Load ◽  
Fracture Surface Morphology ◽  
Commercial Pure Titanium ◽  
Low Load ◽  
Cp Ti

In this paper, the effects of temperature and dwell time on the Fatigue Crack Growth (FCG) behavior of commercial pure titanium were studied under high and low load ratios. Besides, combined with the fracture surface morphology, the specific characteristics of FCG were analyzed under pure fatigue and dwell fatigue conditions. The experiment results show that the FCG rate of commercial pure titanium (CP-Ti) increases with the temperature under low load ratio, and the dwell time increases the FCG rate. Also, the enhancement of the dwell time increases as the temperature rises. The dwell effect tends to be saturated when the temperature rises to 200 °C. Under high load ratio, the FCG rate of CP-Ti also exhibits a temperature-sensitive enhancement. The enhancement effect of the dwell time on the FCG rate under high load ratio is more significant. However, the effect of the hold time on the FCG rate does not increase at 300 °C. The da/dN–ΔK/E FCG curves for CP-Ti have a tendency to approach each other under different load ratios, which indicates that the E-modulus is an important factor for the difference. The effect of dwell time on the FCG behavior of CP-Ti is dominated by the creep deformation mechanism under different load ratios from room temperature to 300 °C. At the same time, the oxidation effect gradually becomes significant as the load ratio increases to 300 °C. The fracture surface morphology shows that the secondary cracks and the roughness increase with temperature or dwell time under low load ratio condition, while, under high load ratio, the effect of creep deformation on the FCG behavior is more obviously enhanced, and plastic deformation is gradually significant with increase of the dimples.

Analysis of the Grain Refinement Mechanism for Commercial Pure Titanium by ECAP and SMAT

2014 ◽  
Vol 937 ◽  
pp. 162-167 ◽  
Author(s):  
Xiao Mei He ◽  
Shan Shan Zhu ◽  
Cong Hui Zhang
Keyword(s):  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Pure Titanium ◽  
Coarse Grained ◽  
Angular Pressing ◽  
Commercial Pure Titanium ◽  
Ultrafine Grained ◽  
Mechanical Attrition ◽  
Refinement Mechanism ◽  
Cp Ti

Equal Channel Angular Pressing (ECAP) and Surface Mechanical Attrition (SMAT) are the two Severe Plastic Deformation (SPD) processes that have been used to process ultrafine grained (UFG) materials. These two kinds of processes have been used to refine the grain size of coarse-grained commercial pure titanium (CP-Ti). The development of microstructure during equal channel angular pressing (ECAP) and surface mechanical attrition (SMAT) of commercial pure titanium (CP-Ti) is investigated to establish the mechanisms of grain refinement. Based on the various experimental results and analysis, it has been found that the high-strain-rate and many direction loading is conducive to the formation of nanograins and also the grains with less than 100 nm cannot be obtained by the single equal channel angular pressing (ECAP).

Severe Plastic Deformation of Commercial Pure Titanium (CP-Ti) for Biomedical Applications: A Brief Review

JOM ◽  
2017 ◽  
Vol 71 (1) ◽  
pp. 256-263 ◽  
Author(s):  
Reza Mahmoodian ◽  
N. Syahira M. Annuar ◽  
Ghader Faraji ◽  
Nadia Dayana Bahar ◽  
Bushroa Abd Razak ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Biomedical Applications ◽  
Pure Titanium ◽  
Commercial Pure Titanium ◽  
Cp Ti

scholarly journals Erosion Corrosion Behavior of Nanostructure Commercial Pure Titanium in Simulated Body Fluid

2019 ◽  
Vol 261 ◽  
pp. 01004
Author(s):  
F. Djavanroodi ◽  
Osama M. Irfan ◽  
Fahad A. Al-Mufadi
Keyword(s):  
Simulated Body Fluid ◽  
Body Fluid ◽  
Pure Titanium ◽  
Hardness Test ◽  
Torsion Test ◽  
Commercial Pure Titanium ◽  
Transmission Electron ◽  
Erosion Corrosion ◽  
Sever Plastic Deformation ◽  
Cp Ti

To date, ECAP technique have been successfully employed to produce Ultra-fine/Nanostructure grain materials, but some materials such as hexagonal closed-packed (HCP) alloys are difficult to process by ECAP at room temperature. In this work, Transmission Electron Microscopy (TEM), Vickers hardness test and Torsion test were employed to confirm the attainment of ultrafine/nanostructured grain (UFG/NSG) commercial pure titanium (CP-Ti) Titanium fabricated by ECAP as a sever plastic deformation process. The samples were pressed by ECAP (route BC) up to four passes at elevated temperature (400° C). Finally, the Erosion-Corrosion (E-C) behavior of ultrafine/nanostructured grain (UFG/NSG) Titanium in a simulated body fluid were investigated through weight loss measurement.

Tensile Properties and Dislocation Strengthening of Commercial Pure Titanium Processed by Equal-Channel Angular Pressing at Liquid Nitrogen Temperature

2011 ◽  
Vol 682 ◽  
pp. 171-176 ◽  
Author(s):  
Xiao Nong Cheng ◽  
Hong Xing Xu ◽  
Xiao Jing Xu ◽  
Zeng Lei Zhang
Keyword(s):  
Tensile Properties ◽  
Liquid Nitrogen ◽  
Equal Channel Angular Pressing ◽  
Pure Titanium ◽  
Domain Size ◽  
Liquid Nitrogen Temperature ◽  
Angular Pressing ◽  
Commercial Pure Titanium ◽  
Dislocation Strengthening ◽  
Cp Ti

Equal channel angular pressing (ECAP) of a quenched commercial pure titanium (CP-Ti) (grade 2) has been successfully performed at liquid nitrogen temperature with an imposed equivalent strain of about ∼0.5, and its microstructures, tensile properties and dislocation strengthening were investigated. High-resolution transmission electron microscopy (HRTEM) shows that the ECAPed CP-Ti presented a microstructure containing lattice distortions, dislocations, stacking defects and deformation twins. Tensile tests indicate that the ECAPed CP-Ti had yield strength of ~700 MPa (40 % higher than that of the unECAPed CP-Ti) and a high level of tensile ductility (~28%). X-ray diffractometer (XRD) data indicate that the ECAP processing not only broaden the XRD peaks significantly but also decreased texture considerably. The theoretical analysis by using Taylor equation based on the coherent diffraction domain size and the lattice micro-strain obtained from XRD line broadening analysis illustrates that ECAP-resulted dislocation made a strengthening contribution of about ~35.1 %.

Deformation Behaviour of a Commercial Pure Titanium Alloy during Hot Compression Testing

2013 ◽  
Vol 773-774 ◽  
pp. 281-286
Author(s):  
Qi Chao ◽  
Hossein Beladi ◽  
Ilchat Sabirov ◽  
Peter Hodgson
Keyword(s):  
Flow Behavior ◽  
Deformation Behaviour ◽  
Pure Titanium ◽  
Hot Compression ◽  
Commercially Pure Titanium ◽  
Commercial Pure Titanium ◽  
Commercially Pure ◽  
Analysis Technique ◽  
Cp Ti ◽  
Electron Back Scattered Diffraction

The flow curve behavior and microstructure evolution of commercially pure titanium (CP-Ti) through uniaxial hot compression was investigated at 850 °C and a strain rate of 0.1/s. Electron back scattered diffraction (EBSD) was employed to characterize the microstructure and crystallographic texture development for different thermomechanical conditions. The stress-strain curves of CP-Ti alloy under hot compression displayed a typical flow behavior of metals undergoing dynamic recrystallization (DRX), which resulted in grain refinement. The critical strain for the onset of DRX was 0.13 using the double differentiation analysis technique. It was also revealed that the texture was markably altered during hot deformation.

Consolidation Process in Near Net Shape Manufacturing of Armstrong CP-Ti/Ti-6Al-4V Powders

2010 ◽  
Vol 436 ◽  
pp. 103-111 ◽  
Author(s):  
Yukinori Yamamoto ◽  
Jim O. Kiggans ◽  
Michael B. Clark ◽  
Stephen D. Nunn ◽  
Adrian S. Sabau ◽  
...  
Keyword(s):  
Time Pressure ◽  
Low Cost ◽  
Pure Titanium ◽  
Cold Isostatic Pressing ◽  
Theoretical Density ◽  
Commercially Pure Titanium ◽  
Consolidation Process ◽  
The Press ◽  
Near Net Shape ◽  
Cp Ti

This paper summarizes our recent efforts to develop the manufacturing technologies of consolidated net-shape components by using new low-cost commercially pure titanium (CP-Ti) and Ti-6Al-4V alloy powders made by the Armstrong process. Fabrication processes of net shape/ near net shape components, such as uniaxial die-pressing, cold isostatic pressing (CIP), sintering, roll compaction and stamping, have been evaluated. The press-and-sinter processing of the powders were systematically investigated in terms of theoretical density and microstructure as a function of time, pressure, and temperature. Up to 96.4% theoretical density has been achieved with the press-and-sinter technology. Tensile properties of the consolidated samples exhibit good ductility as well as equivalent yield/ultimate tensile strengths to those of fully consolidate materials, even with the presence of a certain amount of porosity. A consolidation model is also under development to interpret the powder deformation during processing. Net shape components made of the Armstrong powder can successfully be fabricated with clearer surface details by using press-and-sinter processing.

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