scholarly journals Microstructure Evolution and Mechanical Properties of PM-Ti43Al9V0.3Y Alloy

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 198 ◽  
Author(s):  
Dongdong Zhang ◽  
Na Liu ◽  
Yuyong Chen ◽  
Guoqing Zhang ◽  
Jing Tian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Room Temperature ◽  
Hot Isostatic Pressing ◽  
Electron Backscattered Diffraction ◽  
Tial Alloys ◽  
Fine Grain ◽  
Transmission Electron ◽  
Novel Strategy ◽  
Room Temperature Strength

A novel strategy of microstructure design is introduced to improve the mechanical properties of TiAl alloys, fabricated by powder metallurgy. The gas atomization powder and as-HIPed (Hot isostatic pressing) TiAl are investigated by scanning electron microscopy, energy dispersive spectrometry, transmission electron microscopy, and electron backscattered diffraction. The dispersed submicron precipitate in the microstructure is determined to be Y2O3. A microstructure with uniform fine grain is obtained. The room temperature strength and strain reach 793 MPa and 1.5%, respectively. The strength and strain at 700 °C are still as high as 664 MPa and 9.2%, respectively. The fine grain and precipitate lead to a high room-temperature plasticity.

Preparation of Al2O3/Al-Si Composites by In Situ Reaction of Fe2O3+MnO2/Al System

2015 ◽  
Vol 816 ◽  
pp. 48-53
Author(s):  
Jing Zhang ◽  
Hua Shun Yu ◽  
Xin Ting Shuai ◽  
Hong Mei Chen ◽  
Guang Hui Min
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Electron Probe ◽  
Room Temperature ◽  
Manganese Content ◽  
Hardness Test ◽  
Test Results ◽  
Electron Probe Micro Analyzer ◽  
Transmission Electron ◽  
Polygonal Shape

Al2O3 particles reinforced ZL109 composites were prepared by in-situ reaction between Fe2O3+MnO2 and Al in this paper. The influence of ratio of Mn to Fe on the morphologies of Al-Si-Mn-Fe phase and mechanical properties of the composites was investigated. The microstructure was studied by electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM). The results show that the Al2O3 particles displaced by the Fe2O3+MnO2/Al system are in nanosize. The acicular Al-Si-Fe phases change from acicular to polygonal shape and become smaller with the increase manganese content. The hardness test results have no big difference on the composites. However, the ultimate tensile strength at room temperature and 350°C enhance evidently with the increasing of Mn/Fe.

scholarly journals Effect of a Trace Addition of Sn on the Aging Behavior of Al–Mg–Si Alloy with a Different Mg/Si Ratio

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 913 ◽  
Author(s):  
Lehang Ma ◽  
Jianguo Tang ◽  
Wenbin Tu ◽  
Lingying Ye ◽  
Haichun Jiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Room Temperature ◽  
Number Density ◽  
Precipitation Behavior ◽  
Aging Behavior ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Positive Effect ◽  
Room Temperature Tensile Test

In this paper, the effect of trace Sn on the precipitation behavior and mechanical properties of Al–Mg–Si alloys with different Mg/Si ratios aged at 180 °C was investigated using hardness measurements, a room-temperature tensile test, transmission electron microscopy and differential scanning calorimetry. The results shown that Sn reduces the precipitation activation energy, increases the number density of β″ precipitates, and then increased the aging hardenability and mechanical properties of the Al–Mg–Si alloy. However, the positive effect of Sn on the mechanical properties of the Al–Mg–Si alloy drops with the decrease of the Mg/Si ratio of the alloy.

Grain Refinement of Pure Copper by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 393-398 ◽  
Author(s):  
Nayar Lugo ◽  
Jose María Cabrera ◽  
Núria Llorca-Isern ◽  
C.J. Luis-Pérez ◽  
Rodrigo Luri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Grain Refinement ◽  
Strain Distribution ◽  
Room Temperature ◽  
Pure Copper ◽  
Angular Pressing ◽  
Transmission Electron ◽  
Homogeneous Strain

Pure commercial Cu of 99,98 wt % purity was processed at room temperature by Equal- Channel Angular Pressing (ECAP) following route Bc. Heavy deformation was introduced in the samples after a considerable number of ECAP passes, namely 1, 4, 8, 12 and 16. A significant grain refinement was observed by transmission electron microscopy (TEM). Tensile and microhardness tests were also carried out on the deformed material in order to correlate microstructure and mechanical properties. Microhardness measurements displayed a quite homogeneous strain distribution. The most significative microstructural and mechanical changes were introduced in the first ECAP pass although a gradual increment in strength and a slight further grain refinement was noticed in the consecutive ECAP passes.

The effects of combined cyclic close die forging and aging process on microstructure and mechanical properties of AA7075

2020 ◽  
Vol 234 (9) ◽  
pp. 1242-1251
Author(s):  
MA Moazam ◽  
M Honarpisheh
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Room Temperature ◽  
Crack Formation ◽  
Experimental Tests ◽  
Ultimate Tensile Stress ◽  
X Ray ◽  
Die Forging ◽  
Transmission Electron ◽  
Processed Sample

It is well known that applying severe plastic deformation methods on the precipitation hardenable aluminum alloys at room temperature is very difficult because of crack formation and segmentation of the specimen during the processes. In this study, several procedures were experimentally examined for performing the cyclic close die forging (CCDF) and improving the mechanical properties of AA7075. The experimental tests revealed that supersaturated solid solution of AA7075 after water quenching is formable for only about 5 min and performing the CCDF process in this limited time is possible. Optical and scanning electron microscopy and transmission electron microscopy were used to study the microstructure of the processed samples. It was observed that by applying two passes of CCDF, the grain size of the material reduced from 30 µm to about 200–300 nm. In addition, the X-ray diffractometer results demonstrated that Guinier–Preston zone picks of the processed samples are very weak and the equilibrium η-phase does not exist in none of the suggested procedures. Furthermore, it was found that by combining CCDF and aging processes according to the proposed procedures, the mechanical properties of the processed AA7075 were improved when compared with the AA7075-T6. To put it more clearly, micro-hardness, yield strength and ultimate tensile stress of the processed sample were improved as much as 38.6%, 25% and 23%, respectively.

Optimization of Precipitation Phase Type and Mechanical Properties of X2A66 Alloy by Pre-Deformation Treatment

2019 ◽  
Vol 814 ◽  
pp. 268-274
Author(s):  
Mang Jiang ◽  
Rui Chun Guan ◽  
Jin Jun Xu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Aging Temperature ◽  
Room Temperature ◽  
Transmission Electron ◽  
Phase Type ◽  
New Type ◽  
Precipitation Phase ◽  
Room Temperature Tensile Test ◽  
Deformation Treatment

In the present work, the effects of pre-deformation before aging on the precipitation phase and mechanical properties of a new type X2A66 alloy was investigated with the help of the room temperature tensile test, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) methods. The experimental research results prove that reducing the aging temperature or pre-deformation before aging is beneficial to improve the mechanical properties of the alloy. Compared with decreased aging temperature, pre-deformation treatment before aging can significantly improve the mechanical properties of the alloy, and its yield strength (YS), ultimate tensile strength (UTS) and elongation are 593.4Mpa, 610.8Mpa, and 10.7%, respectively.

scholarly journals Tribo-mechanical properties evaluation of HA/TiO2/CNT nanocomposite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Erfan Zalnezhad ◽  
F. Musharavati ◽  
Tianyi Chen ◽  
Fadi Jaber ◽  
Kaan Uzun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Hot Isostatic Pressing ◽  
Surface Hardness ◽  
Hardness Test ◽  
X Ray ◽  
In Vitro Biocompatibility ◽  
Transmission Electron ◽  
Nanocomposite Powders

AbstractIn this study, a combination of reverse microemulsion and hydrothermal techniques were used to synthesize HA. A hydrothermal method was used to synthesize HA/TiO2/CNT nanocomposite powders. Cold and hot isostatic pressing techniques were used to fabricate tablet-shaped samples. To investigate the biocompatibility and tribo-mechanical properties of HA/TiO2 and HA/TiO2/CNTs, four samples were prepared with different percentages of CNTs, namely, HA/TiO2 (S0), HA/TiO2/CNT (S1.0), HA/TiO2/CNT (S2.0), and HA/TiO2/CNT (S3.0). The microstructure and morphology of the HA/TiO2/CNTs were characterized by transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Hardness test results show that S3.0 displayed the highest surface hardness (285 HV) compared to other samples. The wear rate of HA/TiO2/CNT with the highest CNT content showed a decrease compared with those of the other samples. The results from nanoindentation tests showed that Young’s modulus of the S3.0 sample was 58.1% greater than that of the S0 sample. Furthermore, the human MDA-MB-231 cell line demonstrated good binding to the surface of the samples in the in-vitro biocompatibility evaluation of the HA/TiO2/CNT composites.

Helium Implantation Damage in SiC

2005 ◽  
Vol 108-109 ◽  
pp. 709-712
Author(s):  
Stephanie Leclerc ◽  
Marie France Beaufort ◽  
Valerie Audurier ◽  
Alain Déclemy ◽  
Jean François Barbot
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Helium Ions ◽  
X Ray ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Helium Implantation

Single crystals SiC were implanted with 50 keV helium ions at room temperature and fluences in the range 1x1016 -1x1017 cm-2. The helium implantation induced swelling was studied through the measurement of the step height. The damage was studied by using X-ray diffraction measurements and the transmission electron microscopy observations. Degradation of mechanical properties is found after helium implantation.

Bulk Nanocrystalline Al 7050 Prepared via Cryomilling

2013 ◽  
Vol 779-780 ◽  
pp. 34-42
Author(s):  
Jiong Li Li ◽  
Sha Sha Li ◽  
Yan Cai Xiong
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Bulk Material ◽  
Hot Isostatic Pressing ◽  
Tensile Load ◽  
Hot Extrusion ◽  
Microstructural Investigation ◽  
Cryomilled Powder ◽  
Transmission Electron ◽  
Bulk Nanocrystalline

The operation with a combination of three processing routes: cryomilling, hot isostatic pressing (HIPping) and hot extrusion was adopted in the present study for preparation of the bulk nanocrystalline Al 7050. The microstructure and fractography of the bulk material were observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Furthermore, the chemical composition, density and tensile properties of the material were also measured. Microstructural investigation showed that the grain size of the bulk nanocrystalline Al 7050 ranged from 100nm to 200nm. Numerous dispersoids with a diameter/length of ~50nm were observed on grain boundaries and inside the grains. Besides, one phase of these dispersoids existed in the bulk nanocrystalline Al 7050 was identified as Al6(FeMn). These dispersoids dispersed within the bulk nanocrystalline Al 7050, to some extent, increased the mechanical properties and thermal stability of the material. The resulted sample exhibited ultimate strength of 412MPa with an elongation of 5.2% when tested under tensile load, which was a bit lower than that of the traditionally wrought Al 7050-T6. The present results suggested that improper selected starting powder and milling parameters resulted in the flake-like morphology of the cryomilled powder. The flake-like morphology made it difficult for the cryomilled powder to fill the can entirely and achieve a high density material, which led to the weak interface within the bulk material and in turn degraded the mechanical properties of the bulk nanocrystalline Al 7050 prepared in the present work.

scholarly journals Microstructure and Mechanical Properties of Al-3 Vol% CNT Nanocomposites Processed by High-Pressure Torsion

2017 ◽  
Vol 62 (2) ◽  
pp. 1109-1112 ◽  
Author(s):  
H. Asgharzadeh ◽  
H.S. Kim
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Pressure ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Tensile Ductility ◽  
Tensile Tests ◽  
Tensile Fracture ◽  
Tensile Fracture Surface ◽  
Transmission Electron

Abstract Al-3 vol% CNT nanocomposites were processed by high-pressure torsion (HPT) at room temperature under the pressure in the range of 2.5-10 GPa for up to 10 turns. Optical microscopy, scanning electron microscopy, and transmission electron microscopy (TEM) were used to investigate the microstructural evolutions upon HPT. Mechanical properties of the HPT-processed disks were studied using tensile tests and microhardness measurements. The results show gradual evolutions in the density, microstructure, and hardness with increasing the number of turns and applied presure. Nanostructured and elongated Al grains with an average grain thickness of ~40 nm perpendicular to the compression axis of HPT and an aspect ratio of ~3 are formed after 10 turns under 6 GPa. Evaluating the mechanical properties of the 10-turn processed Al/CNT nanocomposites indicates a tensile strength of 321 MPa and a hardness of 122 Hv. The tensile fracture surface of the Al/CNT nanocomposite mostly demonstrates a smooth fracture manner with fine dimples resulting in a low tensile ductility of ~1.5%.

Effect of Co on microstructure and mechanical properties of precipitation hardening stainless steel

2020 ◽  
Vol 117 (1) ◽  
pp. 116
Author(s):  
Xiang LV ◽  
De-ning Zou ◽  
Jiao Li ◽  
Yang Pang ◽  
Yu-nong Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Stainless Steel ◽  
Precipitation Hardening ◽  
Volume Fraction ◽  
X Ray ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Transmission Electron ◽  
Solution Strengthening

The effects of Co element on the microstructure of precipitation hardening stainless steel was investigated by metallographic microscope (OM), transmission electron microscopy (TEM) and X-ray diffractometry (XRD), and the mechanical properties were measured by tensile, hardness and impact tests. The results show that with increasing Co content, the volume fraction of reversion austenite is increased. The precipitation of ε-Cu phase is remarkably decreased, leading to the improvement of ductility, while the strength and hardness are decreased. Co element improves the strength and toughness of stainless steel through fine-grain strengthening, solution strengthening and austenitic toughening.

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