Strength and ductility optimization of laser additive manufactured metastable β titanium alloy by tuning α phase by post heat treatment

2021 ◽  
pp. 142265
Author(s):  
Xiaotong Pang ◽  
Zhihui Xiong ◽  
Chengwu Yao ◽  
Junhao Sun ◽  
R.D.K. Misra ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Post Heat Treatment ◽  
Α Phase ◽  
Strength And Ductility

scholarly journals Formation of Structure and Properties of Two-Phase Ti-6Al-4V Alloy during Cold Metal Transfer Additive Deposition with Interpass Forging

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4415
Author(s):  
Yuri Shchitsyn ◽  
Maksim Kartashev ◽  
Ekaterina Krivonosova ◽  
Tatyana Olshanskaya ◽  
Dmitriy Trushnikov
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Physical And Mechanical Properties ◽  
Metal Transfer ◽  
Layer By Layer ◽  
Structure And Properties ◽  
Two Phase ◽  
Cold Metal Transfer ◽  
Α Phase ◽  
Cold Metal

The paper deals with the main formation patterns of structure and properties of a titanium alloy of the Ti-6Al-4V system during additive manufacturing using cold metal transfer (CMT) wire deposition. The work aims to find the optimal conditions for layer-by-layer deposition, which provides the high physical and mechanical properties of the titanium alloy of the Ti-6Al-4V system hybrid, additively manufactured using CMT deposition. Particular attention is paid to interpass forging during the layered printing of the product. Additionally, we investigate how the heat treatment affects the structure and properties of the Ti-6Al-4V alloy that has been CMT-deposited, both with and without forging. These studies have shown that the hybrid multilayer arc deposition technology, with interpass strain hardening, allows the use of high temperature and high technology titanium alloys to obtain products of a required geometric shape. It has been proven that the interpass deformation effect during CMT deposition contributes to a significant decrease in the sizes of the primary β-grains. In addition, forging enhances the effect of microstructure refinement, which is associated with phase recrystallization in deformed areas. It is shown that the heat treatment leads not only to a change in the morphology of the phases but also to additional phase formations in the structure of the Ti-6Al-4V-deposited metal while the mechanism is realized and consists of the gradual decomposition of the martensitic α′-phase and the formation of a dispersive α2-phase. This structure formation process is accompanied by the dispersion hardening of the α-phase. The strength characteristics of the Ti-6Al-4V alloy obtained using layer-by-layer CMT with forging are given; they exceed the strength level of materials obtained with the traditional technologies of pressure treatment, and there is no decrease in plasticity characteristics. The use of the subsequent heat treatment makes it possible to increase the ductility characteristics of the deposited and forged Ti-6Al-4V material by 1.5–2 times without strength loss.

Changes in the structural and textural state of titanium alloy VT41 after hot upsetting and annealing

2021 ◽  
pp. 40-50
Author(s):  
P. N. Medvedev ◽  
S. A. Naprienko ◽  
O. S. Kashapov ◽  
E. V. Filonova
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Gas Turbine ◽  
Structural Changes ◽  
Annealing Temperature ◽  
Alloy Structure ◽  
Turbine Engine ◽  
Α Phase ◽  
Deformed State ◽  
Kinetics Of

A study of the structure of titanium alloy VT41 (Ti–Al–Si–Zr–Sn– β-stabilizers) was carried out on a sample subjected to hot upsetting in the (α+β)-region – conditions simulating the stamping of a disk of a gas turbine engine (GTE). The features of the formation of the textural state of primary and secondary globular grains, as well as the kinetics of their dissolution with an increase in the annealing temperature, have been determined. As a result of heat treatment at 995°C, the homogeneity of the alloy structure significantly increases comparing to the deformed state, which is associated with the recrystallization of lamellar and small-globular grains and the retention of primary globular grains of the α-phase. The sequence of structural changes has been established during the annealing within the temperature range from 950 to 1040°C.

Multi-Scale Microstructure Regulation Technology of Near-α High Temperature Titanium Alloy

2019 ◽  
Vol 944 ◽  
pp. 92-98
Author(s):  
Xu Qiao ◽  
Bo Long Li ◽  
Tong Bo Wang ◽  
Zuo Ren Nie
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
High Temperature ◽  
Process Analysis ◽  
Solution Treatment ◽  
Solution Temperature ◽  
Microstructure And Properties ◽  
Equiaxed Structure ◽  
Α Phase ◽  
Α2 Phase

The served harsh environment of advanced aircraft engine puts forward higher requirements for high temperature titanium alloy performance. The optimized heat treatment technology provides effective theoretical basis for improving the microstructure and properties of high temperature titanium alloys. In this paper, we study the influence of different heat treatment systems on microstructure and mechanical properties of high temperature alloy with equiaxed structure, in order to obtain the corresponding relationship between the process and the microstructure performance of the alloy and the optimal heat treatment process. Analysis the effect of solution treatment on the primary α phase quantitatively by optical microscope and Image-Pro-Plus 6.0 software based on the forged high temperature titanium alloy in α+β phase region. Observe the precipitation of α2 phase and silicide by TEM, optimize the aging process according to hardness test. The results show that the content of primary a phase decrease from 63.3% at 920°C to 15.3% at 990°C with the increase of solution temperature. When the temperature rises to 980~990°C, the structure changes from equiaxed structure to α+β duplex microstructure. And change into lamellar structure when the solution temperature raise to 1010°C. The secondary α phase precipitates more fully when the aging temperature increases. And with increasing aging time, the trend of α2 phase growth become more significantly. The optimum heat treatment system obtained in this experimental is 990°C/1h/AC+700°C/5h/AC, and the α phase is about 15.3%. Hence, the excellent microstructure and properties match has been obtained.

scholarly journals The Heat Treatment Influence on the Microstructure and Hardness of TC4 Titanium Alloy Manufactured via Selective Laser Melting

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1318 ◽  
Author(s):  
Zhan-Yong Zhao ◽  
Liang Li ◽  
Pei-Kang Bai ◽  
Yang Jin ◽  
Li-Yun Wu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Critical Temperature ◽  
Selective Laser Melting ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Laser Melting ◽  
Β Phase ◽  
Α Phase ◽  
Increasing Temperature

In this research, the effect of several heat treatments on the microstructure and microhardness of TC4 (Ti6Al4V) titanium alloy processed by selective laser melting (SLM) is studied. The results showed that the original acicular martensite α′-phase in the TC4 alloy formed by SLM is converted into a lamellar mixture of α + β for heat treatment temperatures below the critical temperature (T0 at approximately 893 °C). With the increase of heat treatment temperature, the size of the lamellar mixture structure inside of the TC4 part gradually grows. When the heat treatment temperature is above T0, because the cooling rate is relatively steep, the β-phase recrystallization transforms into a compact secondary α-phase, and a basketweave structure can be found because the primary α-phase develop and connect or cross each other with different orientations. The residence time for TC4 SLM parts when the treatment temperature is below the critical temperature has little influence: both the α-phase and the β-phase will tend to coarsen but hinder each other, thereby limiting grain growth. The microhardness gradually decreases with increasing temperature when the TC4 SLM part is treated below the critical temperature. Conversely, the microhardness increases significantly with increasing temperature when the TC4 SLM part is treated above the critical temperature.

Influence of Electric Pulse Heat Treatment on the Dynamic Mechanical Behavior of TC6 Titanium Alloy

2016 ◽  
Vol 849 ◽  
pp. 340-346 ◽  
Author(s):  
Chuan Hu Pei ◽  
Zhen Xi Li ◽  
Qun Bo Fan ◽  
Jian Shan Ding
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Dynamic Properties ◽  
Electric Pulse ◽  
Dynamic Compression ◽  
Pulse Treatment ◽  
Dynamic Mechanical ◽  
Α Phase ◽  
Pulse Heat ◽  
Electric Pulse Treatment

In order to improve the dynamic mechanical properties of TC6 titanium alloy, the effect of electric pulse heat treatment on the dynamic properties and microstructures of TC6 has been investigated in this paper. It was observed that the secondary α phase was successfully controlled through rapid temperature rising and proper temperature holding by the electric pulse. Compared with traditional heat treatment methods, the electric pulse treatment can obviously refine the grains of secondary α phase. In addition, the refined second α phase distributed uniformly with fine equiaxed and lamellar shapes. As a result, this refined second α phase will resist the expansion of cracks and promote the coordination deformation of grains. According to the dynamic compression test results, it can be found that the adiabatic shear susceptibility of the microstructure obtained from the electric pulse treatment obviously decreased. On the other hand, the dynamic ductility and absorbed energy were much higher than that of the microstructure (equiaxed, bi-modal and basket weave structures) obtained from traditional heat treatments.

Effect of Heat Treatment on the Microstructure and Dynamic Behavior of Ti-10V-2Fe-3Al Alloy

2018 ◽  
Vol 910 ◽  
pp. 155-160 ◽  
Author(s):  
An Jin Liu ◽  
Lin Wang ◽  
Hua Xiang Dai
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Titanium Alloy ◽  
Yield Strength ◽  
Dynamic Compression ◽  
Aging Treatment ◽  
Solution Temperature ◽  
Β Phase ◽  
Solution Treated ◽  
Α Phase

Microstructure evolution and compression property of Ti-10V-2Fe-3Al titanium alloy were studied in this paper. Solution treatments were performed at temperature ranging from 710°C to 830°C and some followed by aging treatment. Ti-10V-2Fe-3Al alloys with α+β phase show higher mechanical properties compared with single β phase alloy. With the increase of solution temperature, the content of equiaxed α phase decrease. Consequently, the strength of the alloy increases while the plasticity drops down. The highest yield strength value of 1668 MPa was obtained in the sample treated by 770°C solution treated for 2 hours then water quenched and followed by 520°C aging for 8 hours then air cooled. The stress induced martensite α'' phase appeared after SHPB dynamic compression in the sample solution treated at 830°C.

Influence of Heating Temperature and Cooling Conditions on Structure and Properties of Two-Phase Titanium Alloy

2017 ◽  
Vol 265 ◽  
pp. 646-651
Author(s):  
F.V. Vodolazskiy ◽  
A.V. Zhloba ◽  
Artemiy A. Popov
Keyword(s):  
Titanium Alloy ◽  
Phase Composition ◽  
Heating Temperature ◽  
Two Phase ◽  
Cooling Conditions ◽  
Α Phase ◽  
Rate Of Cooling ◽  
Temperature Rate ◽  
Cooling Air ◽  
Strength And Ductility

The effects of heating temperature in the range 790-990 ° C and subsequent cooling in the water, in air, with the furnace on the formation of the structure, phase composition of the titanium alloy VST2 were studied. There was the metastable β-solid solution and α - phase during the quenching heating temperature to 865 °C. The phase composition in the temperature range of 865-915 °C was α + β + α''. There was only α'' - martensite in the structure at the temperatures above 940 °C. Reducing the rate of cooling (air, furnace) helped the retention of two-phase α + β - state after all the heating temperatures. The temperature - rate parameters of heat treatment which can obtain good strength and ductility properties are suggested.

scholarly journals The Effects of Post Heat Treatment on the Microstructural and Mechanical Properties of an Additive-Manufactured Porous Titanium Alloy

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 593 ◽  
Author(s):  
Guisheng Yu ◽  
Zhibin Li ◽  
Youlu Hua ◽  
Hui Liu ◽  
Xueyang Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Energy Absorption ◽  
Porous Titanium ◽  
Absorption Efficiency ◽  
Treatment Temperature ◽  
Post Heat Treatment ◽  
Α Phase ◽  
Heat Treated ◽  
Energy Absorption Efficiency

In this work, Ti-6Al-4V (Ti64) porous structures were prepared by selective laser melting (SLM), and the effects of post heat treatment on its microstructural and mechanical properties were investigated. The results showed that as SLM samples were mainly composed of needle-like α′ martensite. Heat treatment at 750 °C caused α′ phase to decompose, forming a lamellar α+β mixed microstructure. As the heat treatment temperature increased to 950 °C, the width of lamellar α phase gradually increased to 3.1 μm. Heat treatment also reduced the compressive strength of the samples; however, it significantly improved the ductility of the porous Ti64. Moreover, heat treatment improved the energy absorption efficiency of the porous Ti64. The samples heat-treated at 750 °C had the highest energy absorption of 233.6 ± 1.5 MJ/m3 at ε = 50%.

Effect of Heat Treatment on the Microstructure Evolution of Ti-6Al-3Sn-3Zr-3Mo-3Nb-1W-0.2Si Titanium Alloy

2016 ◽  
Vol 879 ◽  
pp. 1828-1833 ◽  
Author(s):  
Xiao Yun Song ◽  
Wen Jing Zhang ◽  
Teng Ma ◽  
Wen Jun Ye ◽  
Song Xiao Hui
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Microstructure Evolution ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Water Quenching ◽  
Air Cooling ◽  
Two Phase ◽  
Β Phase ◽  
Α Phase

Ti-6Al-3Sn-3Zr-3Mo-3Nb-1W-0.2Si (BTi-6431S) alloy is a novel two-phase high temperature titanium alloy for short-term using in aerospace industry up to 700°C. The effects of heat treatment on the microstructure evolution of BTi-6431S alloy bar were investigated through optical microscopy (OM), X-ray diffraction (XRD), electron probe microanalysis (EPMA) and transmission electron microscopy (TEM). The results show that solution treatment in β region at 1010°C followed by water quenching results in the formation of orthorhombic martensite α′′ phase, while air cooling leads to the formation of hexagonal martensite α′ phase. When solution-treated in α+β phase field at temperatures from 900°C to 980°C following by water quenching, the content of primary α phase decreases with the increase of heat treatment temperature. For the alloy subjected to identical heat treatment, the content of Al in α phase is much higher than that in β phase, while the contents of Nb, Mo and W elements in α phase are much less than those in β phase.

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