scholarly journals Evolution in Microstructure and Mechanical Properties of Inconel 783 Alloy Bolts after Long Term High-Temperature Aging at 700 °C

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1440 ◽  
Author(s):  
Peng Duan ◽  
Zongde Liu ◽  
Shuchao Gu ◽  
Song Wang
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Aging Time ◽  
Aging Temperature ◽  
Testing Machine ◽  
Impact Testing ◽  
Rapid Decline ◽  
Β Phase ◽  
Microstructure And Mechanical Properties ◽  
Orientation Distributions

This paper described systematically the changes in microstructure and mechanical properties of Inconel 783 alloy after a considerably long time (equivalently 55,000 h, about 76.4 months) of thermal exposure. Based on the Inconel 783 alloy bolts of an intermediate pressure main stop valve used in a 1000 MW ultra-supercritical unit, the evolution of microstructures and mechanical properties were studied after 700 °C aging temperature with different aging times (1000 h, 3000 h and 20,000 h, corresponding to about 1.4 months, 4.2 months and 27.8 months, respectively), using an optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffractometer (XRD), a universal tensile testing machine and impact testing machine. The results indicated that the bolts aged for 1000 h in two temperatures, showing the second needle β phase, of which the quantity and size obviously increased with aging time. Meanwhile, the characteristics in quantity and shape of the primary β phase changed obviously with the aging time, which transformed to strip the Ni5Al3 and Laves-Nb-rich brittle phase in the matrix after aging for 20,000 h. The size of the γ’ phase grew bigger with aging time, and orientation distributions have been observed obviously at 3000 h aging in 700 °C. Compared with the 650 °C aging temperature, the coarsening of γ’ precipitates and second needle β, the orientation distributions of γ’ were more obvious at the 700 °C aging temperature with aging time, which resulted in the rapid decline in yield strength and tensile strength and obvious increase in the brittleness for Inconel 783 alloy bolts.

Enhancement of Mechanical Properties of Cast Beta-Type Titanium Alloy by Aging Treatment

2018 ◽  
Vol 929 ◽  
pp. 42-49
Author(s):  
Zuldesmi Mansjur ◽  
Hendro Maxwel Sumual
Keyword(s):  
Mechanical Properties ◽  
Aging Time ◽  
Vickers Hardness ◽  
Aging Temperature ◽  
Dendritic Structure ◽  
Solution Treatment ◽  
Aging Treatment ◽  
High Oxygen Content ◽  
Precision Casting ◽  
Β Phase

Beta type Ti-29Nb-13Ta-4.6Zr alloy (TNTZ) is one of the titanium alloys which have gained much attention in dental applications. Dental precision casting is predominant for fabricating dental prostheses. However, there is a possibility for the mechanical properties of its casting to be degraded because of a α case, shrinkages and pores and a dendrite structure. One of the ways to enhance their mechanical properties is heat treatment process. Therefore, the aim of this study is to investigate the effect of aging treatment on mechanical properties and microstructure of TNTZ cast into magnesia based mold in order to improve its mechanical properties. As results, the Vickers hardness of the cast TNTZ after solution treatment is larger than that of the wrought TNTZ. The aging curve of the cast and the wrought TNTZ at an aging temperature of 673 K and 723 K exhibit almost similar pattern. For each aging time, the higher the aging temperature, the smaller the Vickers hardness for both alloys. Microstructures of cast TNTZ at various aging conditions consist of a dendritic structure and the average diameters of their grain size are around 40 μm. The diffraction peaks of precipitation of α and β phase s are detected in under aging (UA), peak aging (PA) and over aging (OA) conditions for both aging temperatures. However, the diffraction peak of ω phase is observed only in OA condition for cast TNTZ at aging temperature of 673 K. The highest tensile strength of the cast TNTZ and the wrought TNTZ at both aging temperatures are in PA condition and the elongation decrease continuously by increasing aging time. The tensile strengths of cast TNTZ in UA, PA and OA conditions at an aging temperature of 723 K are lower and their elongations are higher in comparison with those of 673 K. The high oxygen content seems to contribute to the poor elongation. SEM fractographs of the cast TNTZ at aging temperatures of 673 and 723 K in UA, PA and OA conditions show the brittle morphology with intergranular fracture that increases with increasing of aging time.

Microstructure and Mechanical Properties of Joints of X100 Line Pipe by Submerged Arc Welding

2013 ◽  
Vol 310 ◽  
pp. 139-144 ◽  
Author(s):  
Min Zhang ◽  
Liang Yang
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Shear Fracture ◽  
Pipeline Steel ◽  
Testing Machine ◽  
Fracture Morphology ◽  
Impact Testing ◽  
Granular Bainite ◽  
Line Pipe ◽  
The Impact

The microstructure, mechanical properties, fracture morphology and crystal texture of pipeline steel X100 welded joints were investigated using optical electron microscope, scanning electron microscope, tensile and impact testing machine. The results show that, the texture of X100 line pipe mainly consists of acicular ferrite and granular bainite in weld zones, the microstructure of HAZ is coarser, which lead to softening and embrittlement. The fusion line is clear between outer weld and inner weld. The tensile strength of welded joint gets to 803 MPa, which is about 94.81% of the base materials. The impact energy at -10°C is more than 120J, and the average of percent shear fracture appearance at -10°C is up to 85%, is ductile fractures.

Effects of Heat Treatment on Microstructure and Mechanical Properties of Mg-3Sn-2Ca Magnesium Alloy

2012 ◽  
Vol 548 ◽  
pp. 315-320
Author(s):  
Ming Bo Yang ◽  
Ting Zhang Guo ◽  
Hui Li ◽  
Hong Jun Hu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Magnesium Alloy ◽  
Aging Time ◽  
Aging Temperature ◽  
Creep Properties ◽  
Beneficial Effects ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
Matrix Hardness

The effects of heat treatment on the microstructure and mechanical properties of Mg-3Sn-2Ca alloy were investigated. The results indicate that after solutionized at 500 °C for more than 24 h, the morphology of the CaMgSn phase in the alloy changes from the continuous and/or quasi-continuous nets to the particle-like shape. Furthermore, after solutionized at 500 °C for 24 h, for a given aging temperature of 285 °C, with prolonging aging time the matrix hardness of the alloy increases, and attains the maximum at 32 h of aging time and beyond that it decreases. In addition, it is preliminarily inferred that heat treatment would give a beneficial effects on the tensile and creep properties of Mg-3Sn-2Ca alloy due to the modification of the CaMgSn phase.

Effect of Si Content on Microstructure and Properties of 60Si2CrVA Spring Steel

2014 ◽  
Vol 968 ◽  
pp. 63-66 ◽  
Author(s):  
Fei Zhao ◽  
Zhan Ling Zhang ◽  
Jun Shuai Li ◽  
Cui Ye ◽  
Ni Li
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Testing Machine ◽  
Spring Steel ◽  
Impact Testing ◽  
X Ray ◽  
Comprehensive Properties ◽  
Spring Steels ◽  
Si Content

The microstructure and mechanical properties of the four spring steels with different Si content treated by Q-I-Q-T process were studied by metallographic microscope, MTS, impact testing machine and X-ray stress analyzer. The results show that the tensile strength and yield strength is first increased and then decreased with the increase of Si content, the volume fraction of retained austenite and elongation are fist decreased and then increased when the Si content is less than 2.1%, and the microstructure become finer and homogeneous. When Si content reaches 2.1%, the comprehensive properties of 60Si2CrVA spring steel is the best.

scholarly journals Tailoring Microstructure and Mechanical Properties of Additively-Manufactured Ti6Al4V Using Post Processing

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 658
Author(s):  
Yaron Itay Ganor ◽  
Eitan Tiferet ◽  
Sven C. Vogel ◽  
Donald W. Brown ◽  
Michael Chonin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Fatigue Resistance ◽  
Electron Beam Melting ◽  
High Reliability ◽  
National Laboratory ◽  
Post Processing ◽  
Proof Stress ◽  
Β Phase ◽  
Microstructure And Mechanical Properties

Additively-manufactured Ti-6Al-4V (Ti64) exhibits high strength but in some cases inferior elongation to those of conventionally manufactured materials. Post-processing of additively manufactured Ti64 components is investigated to modify the mechanical properties for specific applications while still utilizing the benefits of the additive manufacturing process. The mechanical properties and fatigue resistance of Ti64 samples made by electron beam melting were tested in the as-built state. Several heat treatments (up to 1000 °C) were performed to study their effect on the microstructure and mechanical properties. Phase content during heating was tested with high reliability by neutron diffraction at Los Alamos National Laboratory. Two different hot isostatic pressings (HIP) cycles were tested, one at low temperature (780 °C), the other is at the standard temperature (920 °C). The results show that lowering the HIP holding temperature retains the fine microstructure (~1% β phase) and the 0.2% proof stress of the as-built samples (1038 MPa), but gives rise to higher elongation (~14%) and better fatigue life. The material subjected to a higher HIP temperature had a coarser microstructure, more residual β phase (~2% difference), displayed slightly lower Vickers hardness (~15 HV10N), 0.2% proof stress (~60 MPa) and ultimate stresses (~40 MPa) than the material HIP’ed at 780 °C, but had superior elongation (~6%) and fatigue resistance. Heat treatment at 1000 °C entirely altered the microstructure (~7% β phase), yield elongation of 13.7% but decrease the 0.2% proof-stress to 927 MPa. The results of the HIP at 780 °C imply it would be beneficial to lower the standard ASTM HIP temperature for Ti6Al4V additively manufactured by electron beam melting.

Microstructure and mechanical properties of 15-5 PH stainless steel under different aging temperature

2021 ◽  
Vol 118 (6) ◽  
pp. 601
Author(s):  
Chunhui Jin ◽  
Honglin Zhou ◽  
Yuan Lai ◽  
Bei Li ◽  
Kewei Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Aging Temperature ◽  
Electron Backscatter Diffraction ◽  
Lath Martensite ◽  
Optical Microscope ◽  
Second Phase ◽  
Strengthening Mechanisms ◽  
Microstructure And Mechanical Properties ◽  
Transmission Electron

The influence of aging temperature on microstructure and mechanical properties of Cr15Ni5 precipitation hardening stainless steel (15-5 PH stainless steel) were investigated at aging temperature range of 440–610 °C. The tensile properties at ambient temperature of the 15-5 PH stainless steel processed by different aging temperatures were tested, and the microstructural features were further analyzed utilizing optical microscope (OM), transmission electron microscope (TEM), electron backscatter diffraction (EBSD) as well as X-ray diffraction (XRD), respectively. Results indicated the strength of the 15-5 PH stainless steel was firstly decreased with increment of aging temperature from 440 to 540 °C, and then increased with the increment of aging temperature from 540 to 610 °C. The strength and ductility were well matched at aging temperature 470 °C, and the yield strength, tensile strength as well as elongation were determined to be 1170 MPa, 1240 MPa and 24%, respectively. The microstructures concerning to different aging temperatures were overall confirmed to be lath martensite. The strengthening mechanisms induced by dislocation density and the second phase precipitation of Cu-enriched metallic compound under different aging temperatures were determined to be the predominant strengthening mechanisms controlling the variation trend of mechanical properties corresponding to different aging temperatures with respect to 15-5 PH stainless steel.

Effect of Annealing Temperature on the Microstructure of 2195 Al-Li Alloy Sheet

2021 ◽  
Vol 1026 ◽  
pp. 49-58
Author(s):  
Bo Feng ◽  
Bai Qing Xiong
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Annealing Temperature ◽  
Testing Machine ◽  
Annealing Treatment ◽  
Alloy Sheet ◽  
Transmission Electron ◽  
Δ Phase ◽  
Backscattered Electron ◽  
Alloy Increase

The annealing temperature is a key parameter for the mechanical properties and microstructure control of the 2195 Al-Li alloy sheet in the annealing process. In the present study, the effect of annealing temperature on the microstructure of 2195 Al-Li alloy sheet was investigated using a general mechanical testing machine, scanning electron microscope (SEM), transmission electron microscope (TEM), and backscattered electron microscope (EBSD). It was found that the optimized annealing temperature for 2195Al-Li alloy sheet of H112 state is 400°C, the alloy sheet shows the satisfactory mechanical properties. In addition, with the increase of annealing temperature, the δ' phase, the θ' phase and the T1 phase are formed in the alloy sheet, which leads to the strength of the alloy increase. Furthermore, the annealing temperature obviously affect the texture component and intensity during annealing treatment process.

scholarly journals Effect of Heat Treatment on Microstructure and Mechanical Properties of New Cold-Rolled Automotive Steels

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1414
Author(s):  
Fei Huang ◽  
Jian Chen ◽  
Zhangqi Ge ◽  
Junliang Li ◽  
Yongqiang Wang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Testing Machine ◽  
Second Phase ◽  
Isothermal Heat Treatment ◽  
Austenitizing Temperature ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Microstructure And Mechanical Properties ◽  
Cold Rolled

The effect of austenitizing temperature and aging treatment on the microstructure and mechanical properties of two new cold-rolled automotive steel plates (20Mn2Cr and 20Mn2CrNb) was investigated by using isothermal heat treatment, optical microscope, scanning electron microscope, microhardness tester, and tensile testing machine. The results show that as the austenitizing temperature increased, the original austenite grain sizes of both steels increased. The original austenite grain size of 20Mn2CrNb was smaller than that of 20Mn2Cr. The microhardness of 20Mn2CrNb gradually decreased with increasing aging temperature, while the hardness of 20Mn2Cr varied irregularly. The mechanical properties of 20Mn2Cr were better than those of 20Mn2CrNb under the same heat-treatment process. The effect of heat treatment on microstructure and mechanical properties was related to the martensite content, dislocation density, and precipitation of second-phase particles.

Mechanical Properties of PVC/ABS Composite Material

2011 ◽  
Vol 217-218 ◽  
pp. 1170-1173
Author(s):  
Wei Wei Qiao ◽  
Hui Wang ◽  
Yan Hua Zhao ◽  
Yi Xia Han
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Testing Machine ◽  
Impact Testing ◽  
Elongation At Break ◽  
Poly Vinyl Chloride ◽  
Maximum Value ◽  
Material Testing Machine ◽  
The Impact ◽  
Butadiene Styrene

We investigate the mechanical properties of Poly Vinyl Chloride (PVC)/ acrylnitrile-butadiene-styrene copolymer (ABS) composite material with an impact testing machine，a material testing machine and other accessory devices. The result shows that the mechanical properties of PVC/ABS composite are a function of composition, the addition of ABS improved the mechanical properties of PVC/ ABS composite，the impact strength and elongation at break rise significantly with increasing ABS content in PVC/ABS composite and appears maximum value，While the tensile strength and modulus almost decrease monotonously with increasing ABS content in PVC/ABS composite.

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