scholarly journals The Effect of Heat Treatments on Microstructure and Mechanical Properties of As-Extruded Ti-6Al-4V Alloy Rod from Blended Elemental Powders

2018 ◽  
Vol 770 ◽  
pp. 45-51
Author(s):  
Carlos Romero ◽  
Fei Yang ◽  
Stiliana Raynova ◽  
Leandro Bolzoni

In this study, Ti-6Al-4V bars were first prepared by extrusion of powder compacts from blended powder mixtures in the beta phase region, then the as-extruded bars were heat-treated following four different conditions: beta quenching and aging (βQA), broken up structure (BUS) treatment, solution treatment and aging (STA) and recrystallization annealing (RA). The effect of the heat treatments on microstructure and mechanical properties was studied using optical microscopy, scanning electron microscopy, and mechanical test to determine which heat-treatment condition has the greatest impact on the mechanical properties of the as-extruded Ti-6Al-4V alloy. The results show that the as-extruded condition has the best balance of strength (1120 MPa of UTS) and ductility (11% of elongation to failure). βQA and STA lead to a slight increase in strength but ductility decreases considerably. After BUS and RA treatments, both strength and ductility are reduced. The relationship between processing, microstructure and properties was studied, and their implications towards fatigue behaviour and fracture toughness were discussed.

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1318
Author(s):  
Yunlong Zhang ◽  
Yanbin Chen ◽  
Wang Tao ◽  
Zhenglong Lei ◽  
Zhaohui Yang ◽  
...  

The durable structure and robustness of T-joints in the panel materials for civil aircraft are a crucial matter of importance. In this work, the impact of the post-weld heat treatments (PWHTs) on the microstructure and mechanical properties of laser beam welded T-joints of 2060-T3/2099-T3 Al-Li alloy was analyzed. Heat-treatment of the laser beam welded T-joints was carried out in two different ways, namely, solution treatment and artificial aging (STAA) at varied duration and only artificial aging (AA) at varied duration. The microstructure and mechanical properties of the heat-treated joints were investigated using metallographic and scanning electron microscopic images, micro-hardness test, and tensile test, respectively. The results showed that, in cases of STAA, the eutectic structures on the grain boundary were partially dissolved via solution treatment (ST), and increased dispersed precipitation of the second phase in matrix resulted in significant dispersion strengthening, as well as enhanced strength and plasticity. In contrast, in the AA process, alloy elements in the matrix continued to segregate towards the grain boundary, resulting in significant grain boundary strengthening, enhanced strength, and decreased plasticity. Additionally, joint fractures were micro-porous aggregation transgranular ones in the fusion zone (FZ). The joints treated by STAA exhibited excellent plasticity compared with those treated by AA. Furthermore, the micro-hardness of welded joints treated by AA was higher than that of those treated by STAA. Indeed, the tensile strength of joints treated by STAA and AA ranged from 405 to 475 MPa, which was 81–95% of the base metal 2060-T8, though the elongation of joints treated by STAA was superior to the counterpart AA.


2019 ◽  
Vol 944 ◽  
pp. 73-78
Author(s):  
En Tao Dong ◽  
Wei Yu ◽  
Qing Wu Cai ◽  
Jia Xin Shi ◽  
Zhen Ning ◽  
...  

The properties of titanium alloys significantly depend on the microstructure, which are correspond to the deformation conditions. However, because of its low thermal conductivity, sensitive to deformation temperature, narrow stable regions for hot working and structural heterogeneity, it does not achieve cosmically industrial production and application. In this paper, the effects of hot rolling deformation in single-phase (β) region, cross-phase region and heat treatment on the microstructure and mechanical properties of Ti-6Al-4V ELI alloy were systematically investigated. The relationship between microstructure and properties of alloy was also analyzed in order to a theoretical basis for the development of the rolling technology for the manufacture. The results indicated that hot rolling deformation in different region had significant effects on microstructure heterogeneity (the size and colony of α phase, lamellar microstructure of β transformed). It has been shown that fine and coarse lamellar α structure within grains and visible grain boundary α were characterized after the deformation above the β transformation temperature, which made high impact toughness. But in order to ensure in single phase region, the heat preservation method after passes of rolling may cause β grain coarsening (widmanstatten structure), leading to mechanical properties worsen. The fine crisscross substructures of α phase was obtained after deformation in cross-phase region, improving good mechanical properties. After solution treatment followed aging, the uniform type of microstructure was reached, which mainly displayed the change of contents and sizes of lamellar α phase.


Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 694
Author(s):  
Junaidi Syarif ◽  
Mohammad H. Yousuf ◽  
Zainuddin Sajuri ◽  
Amir Hossein Baghdadi ◽  
Mahdi Merabtene ◽  
...  

The 440C martensitic stainless steel is considered to be among the hardest steels, owing to its high carbon content. Careful heat treatment of this material introduces multiple carbide particles, which can alter microstructure and mechanical properties. This study focused on the effect of austenitisation temperature on the microstructure and tensile properties of 440C steel. Austenitisation was performed on the austenite + carbide region, because 440C steel lacks a single-phase region. The steel was austenitised at two different temperatures; namely, 1160 °C and 950 °C, and subjected to oil quenching. The as-quenched samples showed a typical lath martensite structure with retained austenite phase. The treatments at 1160 °C and 950 °C promoted the formation of M7C3 and M23C6 carbides, respectively. The austenite grains in the sample treated at 1160 °C showed a higher growth rate than those in the sample treated at 950 °C. The sample treated at 1160 °C showed low-fraction and a large-size carbide phase. The Zener pinning force decreased, thereby increasing the austenite grain growth in the sample treated at 1160 °C. The hardness and 0.2% proof stress of the sample treated at 950 °C were higher than those of the sample treated at 1160 °C, owing to the higher martensite content in the former. The strength–ductility balance of the sample treated at 950 °C was higher than that of the sample treated at 1160 °C. The decreased austenitisation temperature resulted in improved mechanical properties of the steel. Therefore, the austenitisation temperature alters the microstructure and mechanical properties of 440C steel.


2012 ◽  
Vol 628 ◽  
pp. 482-485
Author(s):  
Yulia A. Lukina ◽  
Andrey V. Stepanov ◽  
Evgeny N. Bobrov

The paper deals with manufacturing technology for the forged rolls and sleeves from adamite steel at Electrostal Plant of Heavy Machinery (JSC «EZTM»). The influence of different heat treatments on microstructure and mechanical properties of the level of adamite steel is presented.


Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 790 ◽  
Author(s):  
Changping Tang ◽  
Kai Wu ◽  
Wenhui Liu ◽  
Di Feng ◽  
Xuezhao Wang ◽  
...  

The effects of Gd, Y content on the microstructure and mechanical properties of Mg-Gd-Y-Nd-Zr alloy were investigated using hardness measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and uniaxial tensile testing. The results indicate that the alloys in as-cast condition mainly consist of α-Mg matrix and non-equilibrium eutectic Mg5.05RE (RE = Gd, Y, Nd). After solution treatment, the non-equilibrium eutectics dissolved into the matrix but some block shaped RE-rich particles were left at the grain boundaries and within grains. These particles are especially Y-rich and deteriorate the mechanical properties of the alloys. Both the compositions of the eutectic and the block shaped particle were independent of the total Gd, Y content of the alloys, but the number of the particles increases as the total Gd, Y content increases. The ultimate tensile strength increases as the total Gd, Y content decreases. A Mg-5.56Gd-3.38Y-1.11Nd-0.48Zr alloy with the highest ultimate tensile strength of 280 MPa and an elongation of 1.3% was fabricated. The high strength is attributed to the age hardening behavior and the decrease in block shaped particles.


2018 ◽  
Vol 284 ◽  
pp. 615-620 ◽  
Author(s):  
R.M. Baitimerov ◽  
P.A. Lykov ◽  
L.V. Radionova

TiAl6V4 titanium base alloy is widely used in aerospace and medical industries. Specimens for tensile tests from TiAl6V4 with porosity less than 0.5% was fabricated by selective laser melting (SLM). Specimens were treated using two heat treatment procedures, third batch of specimens was tested in as-fabricated statement after machining. Tensile tests were carried out at room temperature. Microstructure and mechanical properties of SLM fabricated TiAl6V4 after different heat treatments were investigated.


2013 ◽  
Vol 43 ◽  
pp. 66-73 ◽  
Author(s):  
Caixiong Yang ◽  
Yulai Xu ◽  
Heng Nie ◽  
Xueshan Xiao ◽  
Guoqing Jia ◽  
...  

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 385
Author(s):  
Yushi Qi ◽  
Heng Wang ◽  
Lili Chen ◽  
Hongming Zhang ◽  
Gang Chen ◽  
...  

A ZK61-Y magnesium (Mg) alloy wheel hub was prepared via liquid forging—isothermal forging process. The effects of Y-element contents on the microstructure and mechanical properties of liquid forging blanks were investigated. The formation order of the second phase was I-phase (Mg3Zn6Y) → W-phase (Mg3Zn3Y2) → Z-phase (Mg12ZnY) with the increase of the Y-element content. Meanwhile, the I-phase and Z-phase formed in the liquid forging process were beneficial to the grain refinement. The numerical simulation of the isothermal forging process was carried out to analyze the effects of forming temperature on the temperature and stress field in the forming parts using the software Deform-3D. Isothermal forging experiments and post heat treatments were conducted. The influence of isothermal forging temperature, heat treatment temperature and preservation time on the microstructure and mechanical properties of the forming parts were also studied. The dynamic recrystallization (DRX), second-phase hardening, and work hardening account for the improvement of properties after the isothermal forging process. The forming part forged at 380 °C displayed the outstanding properties. The elongation, yield strength, and ultimate tensile strength were 18.5%, 150 MPa and 315 MPa, respectively. The samples displayed an increased elongation and decreased strength after heat treatments. The 520 °C—1 h sample possessed the best mechanical properties, the elongation was 25.5%, the yield stress was 125 MPa and the ultimate tensile strength was 282 MPa. This can be ascribed to the recrystallization and the elimination of working hardening. Meanwhile, the second phase transformation (I-phase → W-phase → Mg2Y + MgZn2), dissolution, and decomposition can be observed, as well.


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