scholarly journals The Influence of Heat Input on the Microstructure and Properties of Wire-Arc-Additive-Manufactured Al-Cu-Sn Alloy Deposits

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 79
Author(s):  
Shuai Wang ◽  
Huimin Gu ◽  
Wei Wang ◽  
Chengde Li ◽  
Lingling Ren ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Grain Boundary ◽  
Heat Input ◽  
Raw Material ◽  
Layer Height ◽  
Transmission Electron ◽  
The Matrix ◽  
Wire Arc Additive Manufacturing ◽  
Scanning Electron

In this experiment, Al-Cu-Sn alloy was used as raw material to form deposits with different heat input using the wire-arc additive manufacturing (WAAM) process. The effects of heat input on microstructure and mechanical properties of Al-Cu-Sn alloy deposits were investigated by metallography, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM) and mechanical properties tests. The results show that with increased of heat input, the thickness of the deposits increased and the layer height of the deposits increased. The number and size of pores in the deposits also improved with the increased heat input. The grain size of the deposits in the as-deposited state gradually increased and changed from isometric crystals to columnar crystals, the precipitated θ phases gradually converged on the grain boundary from within the grains. After T6 heat treatment, with increased heat input, the number of unsolved θ phases on the grain boundary increased, and the number of θ phases precipitated out of the matrix decreased as the phase spacing increased. With the increased heat input, the mechanical properties of the deposits gradually decreased, and the fracture mode changed from ductile fracture to brittle fracture.

Microstructure Evolution and Mechanical Properties of an Al-Cu-Mg Alloy at Elevated Temperature

2014 ◽  
Vol 1004-1005 ◽  
pp. 148-153
Author(s):  
Min Hao ◽  
Ji Gang Ru ◽  
Ming Liu ◽  
Kun Zhang ◽  
Liang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Shear Fracture ◽  
S Phase ◽  
Mg Alloy ◽  
Transmission Electron ◽  
Fracture Features ◽  
Scanning Electron

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to study the microstructure and mechanical behavior of an Al-Cu-Mg alloy after tensile test at 125°C, 150°C, 175°C and 200 °C, respectively. The yield strength and ultimate tensile strength decreased with the increase of temperature, while the elongation increased firstly and then decreased. The S and S′ precipitate after tension at elevated temperatures. When the temperature was higher than 175°C, the precipitate coarsens rapidly. The alloys displayed a shear fracture features at elevated temperature. The larger S′ and S phase coarsened and dropped which forming crack in the grain boundaries and precipitate interfaces, resulting in the decrease of the elongation of the alloy.

The Impact Properties of a Polyurethane Composite Filled with Clay

2011 ◽  
Vol 197-198 ◽  
pp. 1100-1103
Author(s):  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Mechanical Analysis ◽  
Impact Testing ◽  
Impact Properties ◽  
Polyurethane Composite ◽  
The Matrix ◽  
The Impact ◽  
Scanning Electron

A polyurethane/clay (PU/clay) composite was synthesized. The microstructure of the composite was examined by scanning electron microscopy. The impact properties of the composite were characterized by impact testing. The study on the structure of the composite showed that clays could be dispersed in the polymer matrix well apart from a few of clusters. The results from mechanical analysis indicated that the impact properties of the composite were increased greatly in comparison with pure polyurethane. The investigation on the mechanical properties showed that the impact strength could be obviously increased by adding 20 wt% (by weight) clay to the matrix.

scholarly journals Study on Grain Refinement Mechanisms and Mechanical Properties of bi-Modal Ti-55511 Titanium Alloy during Hot Rolling

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3351 ◽  
Author(s):  
Wei Chen ◽  
Xiaoyong Zhang ◽  
YongCheng Lin ◽  
Kechao Zhou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hot Rolling ◽  
Shear Bands ◽  
High Ductility ◽  
Α Phase ◽  
Transmission Electron ◽  
Scanning Electron

Multi-pass hot rolling was performed on bi-modal Ti-55511 alloy with 50% rolling reduction at 700 °C. Mechanical properties were evaluated by tensile test, and microstructure evolution was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the Ti-55511 alloy with bi-modal microstructure exhibits good strength and high ductility (1102 MPa, 21.7%). Comparatively, after 50% hot rolling, an enhanced strength and decreased ductility were obtained. The refinement of α phases leads to the increased tensile strength, while the fragmentation of the equiaxed α phase results in a decreased ductility. The fragmentation process of equiaxed α phases followed the sequence of: elongation of α phases → formation of grooves and localized shear bands → the final fragmentation accomplished via deepening grooves.

scholarly journals The Influence of A Mo Addition on the Interfacial Morphologies and Corrosion Resistances of Novel Fe-Cr-B Alloys Immersed in Molten Aluminum

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 256 ◽  
Author(s):  
Zicheng Ling ◽  
Weiping Chen ◽  
Weiye Xu ◽  
Xianman Zhang ◽  
Tiwen Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Probe ◽  
Molten Aluminum ◽  
Dendritic Structure ◽  
H13 Steel ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Scanning Electron

The influence of a Mo addition on the interfacial morphologies and corrosion resistances of novel Fe-Cr-B alloys in molten aluminum at 750 °C was systematically investigated using scanning electron microscopy, X-ray diffractometer, electron probe microanalysis, and transmission electron microscopy. The results indicated that Mo could not only strengthen the matrix but also facilitate the formation of borides. Furthermore, the microstructures of Mo-rich M2B boride changed from a local eutectic net-like structure to a typical coarse dendritic structure and a blocky hypereutectic structure with increasing Mo addition. This was true of the blocky Mo-rich M2B boride, rod-like Cr-rich M2B boride and the corrosion products, which had a synergistic effect on retarding of the diffusion of molten aluminum. Notably, the corrosion resistance of the Fe-Cr-B-Mo alloy, with an 8.3 wt.% Mo addition, was 3.8 times higher than that of H13 steel.

scholarly journals Effect of Cu on the Fracture and Exfoliation Corrosion Behavior of Al-Zn-Mg-xCu Alloy

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1048 ◽  
Author(s):  
Huibin Jiao ◽  
Kanghua Chen ◽  
Songyi Chen ◽  
Zhen Yang ◽  
Peng Xie ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Exfoliation Corrosion ◽  
Cu Content ◽  
Short Transverse ◽  
Transmission Electron ◽  
Corrosion Behaviors ◽  
Mechanical Tensile ◽  
Scanning Electron ◽  
Better Than

In the present work, the influence of Cu content on microstructure, mechanical properties and exfoliation corrosion behaviors of Al-Zn-Mg-xCu alloy extrusions has been investigated in longitudinal-transverse (L-T) and short-longitudinal (S-L) directions by means of mechanical tensile and exfoliation corrosion testing combined with optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that a higher Cu content significantly decreased the fracture toughness and ductility of the alloy in S-L direction compared with L-T direction. Concomitant with the increase in Cu content, a transition in fracture mode was observed from transgranular dimpled rupture to intergranular rupture in S-L direction. Moreover, the exfoliation corrosion (EXCO) resistance of the alloy decreased as the Cu content increased and the exfoliation corrosion resistance of the alloy in short-transverse (S-T) direction was better than that of L-T direction. These results were mainly associated with the large number of coarse intermetallics caused by high Cu content in the L-T direction of alloy.

Surface-modified halloysite nanotubes as fillers applied in reinforcing the performance of polytetrafluoroethylene

Clay Minerals ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 643-656 ◽  
Author(s):  
Zhi-Lin Cheng ◽  
Xing-Yu Chang ◽  
Zan Liu ◽  
Dun-Zhong Qin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Sodium Dodecyl ◽  
Halloysite Nanotubes ◽  
Angle Measurements ◽  
Transmission Electron ◽  
Contact Angle Measurements ◽  
Ftir Spectrometry ◽  
Surface Modified ◽  
Scanning Electron

ABSTRACTIn order to improve the dispersibility of halloysite nanotubes (HNTs) in polytetrafluoroethylene (PTFE), the modification of HNT surfaces was studied with three types of modifiers (polymethyl methacrylate [PMMA], sodium dodecyl sulfate [SDS] and carboxylic acid). The modified HNTs were characterized by Fourier-transform infrared (FTIR) spectrometry, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and contact angle measurements. The HNTs were used to reinforce the mechanical properties of PTFE. The mechanical results indicated that the tensile strength of the modified HNT-filled PTFE nanocomposites (F-HNT/PTFE) improved to an acceptable degree and Young's modulus increased significantly. The tribological results showed that the wear rate of F-HNT/PTFE decreased by 21–82 and 9–40 times compared to pure PTFE and the pristine F-HNT/PTFE, respectively.

scholarly journals TEM observation of precipitates and their role to mechanical properties in Ti-5553 alloy heated to some temperatures up to 923 K

2020 ◽  
Vol 321 ◽  
pp. 11035
Author(s):  
E. Sukedai ◽  
E. Aeby-Gautier ◽  
M. Dehmas
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Hardening Mechanism ◽  
Transmission Electron ◽  
The Matrix ◽  
Higher Temperature ◽  
Shearing Mechanism ◽  
Hardness Values ◽  
Measured Hardness

A Ti-5553 specimen was continuously heated to 923 K and simultaneously in-situ HEXRD profiles were taken. In addition, specimens heated at the same rate to several temperatures up to 923 K and further quenched were observed by transmission electron microscopy. Based on both results obtained, transformation sequence was clarified, precipitations of ω-, α”iso- and α-phases were confirmed, and size and density of these precipitates were measured. Hardness values of those specimens were also measured. The hardening mechanism was considered as shearing-mechanism for specimens aged at lower temperatures and by-pass one for specimens aged at higher temperature. An attempt of distinction between α”iso - and α-precipitates was also tried. Both precipitates were in needle-like shape and a possibility was suggested by measuring angles between two needle-shape precipitates on {110} of the matrix and comparing with each other.

scholarly journals Development of Flexible Polyurethane Nanostructured Biocomposite Foams Derived from Palm Olein-Based Polyol

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Srihanum Adnan ◽  
Tuan Noor Maznee Tuan Ismail ◽  
Norhayati Mohd Noor ◽  
Nik Siti Mariam Nek Mat Din ◽  
Nurul ‘Ain Hanzah ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Palm Olein ◽  
Nanocomposite Foams ◽  
Transmission Electron ◽  
Flexible Polyurethane ◽  
Pu Foams ◽  
Scanning Electron

This study examined the effect of organoclay montmorillonite (OMMT) on the mechanical properties and morphology of flexible polyurethane/OMMT nanocomposite (PU/OMMT) foams prepared from petroleum- and palm olein-based polyols. Palm-based PU foams exhibited inferior mechanical strength as compared to neat petroleum PU foams. However, addition of OMMT significantly improved the foams strength of flexible polyurethane/OMMT nanocomposite foams prepared from palm olein-based polyol (PU bionanocomposite foam). The morphology analysed by scanning electron microscopy (SEM) showed that the cell size of the foam decreased with increasing OMMT content. PU bionanocomposite foam with 5 wt% of OMMT had the most improved tensile (63%) and tear (48%) strengths compared to its neat counterpart. Transmission electron microscopy (TEM) revealed the exfoliated structure of the respective foam. It was concluded that OMMT improved mechanical properties and morphology of PU foams.

Effects of Thermal Treatment on the Morphology and Properties of CSM/Poly(Urethane-Isocyanurate) Composites Formed by SRIM Process

2008 ◽  
Vol 575-578 ◽  
pp. 941-946
Author(s):  
Hong Yan Tang ◽  
Ji Hui Wang ◽  
Guo Qiang Gao ◽  
Wen Xing Chen
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Treatment Time ◽  
Microphase Separation ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Scanning Electron

Fiberglass continuous strand mat(CSM)/poly(urethane-isocyanurate) composites were formed by SRIM process, treated under different conditions and then characterized based on dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) ,transmission electron microscopy (TEM) and the mechanical property tests. The results show that the mechanical properties of the composites could be increased with improving the degree of microphase separation. At a given temperature (120°C), the degree of microphase separation is the highest for 4h and decreases gradually with prolonging treatment time. For a given time (4h), the well microphase-separated morphology is obtained and the degree of microphase mixing is increased at 120°C and 140°C treatments, respectively. The degree of microphase separation of the composites decreases with enhancing the temperature to 140°C.

scholarly journals Effect of Two-Stage Homogenization Heat Treatment on Microstructure and Mechanical Properties of AA2060 Alloy

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 40
Author(s):  
Chaoyang Chaoyang ◽  
Guangjie Guangjie ◽  
Lingfei Lingfei ◽  
Fei Fei ◽  
Lin Lin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Cast Alloy ◽  
Hardness Test ◽  
Test Methods ◽  
Al Alloy ◽  
Two Stage ◽  
Homogenization Treatment ◽  
Transmission Electron ◽  
The Matrix

The microstructure evolution of AA2060 Al alloy containing Li during two-stage homogenization treatment was investigated by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC), transmission electron microscopy (TEM), mechanical properties and Vickers micro-hardness test methods. The results demonstrate that severe precipitation of θ(Al2Cu) and S(Al2CuMg) phase existed in the as-cast alloy, especially in the center position. Cu elements were concentrated at grain boundary and gradually decreased from the boundary to the interior. Numerous eutectic phases of θ(Al2Cu) and S (Al2CuMg) containing Zn and Ag elements were segregated at grain boundaries. The overheating temperature of the as-cast alloy is 497 °C. After two-stage homogenization treatment, the θ(Al2Cu) and S (Al2CuMg) in the surface, middle and center positions were completely dissolved into the matrix, thus achieved uniform homogenization effect. Moreover, water cooling could prevent the precipitation after homogenization, which provided good performance of the studied alloy. The optimum two-stage homogenization treatment of AA2060 alloy was 460 °C/4 h + 490 °C/2 4 h. The homogenization kinetic analysis was discussed as well.

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