Graphite/Copper Composites with High Density

2015 ◽  
Vol 723 ◽  
pp. 475-480 ◽  
Author(s):  
Yong Ping Jin ◽  
Bin Guo
Keyword(s):  
Electron Microscope ◽  
Powder Metallurgy ◽  
Relative Density ◽  
Milling Time ◽  
Sintering Temperature ◽  
Optical Microscope ◽  
Difficult Problem ◽  
Copper Compound ◽  
Technological Parameters ◽  
Scanning Electron

It is a difficult problem how to obtain the density of powder metallurgy products. Sintering billets had been prepared by mechanical milled graphite/copper compound powders firstly. Their microstructures had been analyzed by such means as scanning electron microscope (SEM) and optical microscope. Influence of technological parameters on relative density had also been investigated. The results show that sintering of non-milled powders are intensely affected by sintering temperature, contrary to mechanical milled compound powders. Hot pressed sintering under vacuum can promote densification effectively. By prolonging time, elevating temperature or pressure of hot pressed sintering, relative density of sintering billets can be increased accordingly. Under the same conditions, relative density decreases with mechanical milling time of compound powders.

scholarly journals Studying the Microstructure of Al-Ti Alloy Prepared by Powder Metallurgy using Three Different Percentages of Ti

2020 ◽  
Vol 26 (6) ◽  
pp. 132-139
Author(s):  
Sahib Mohammed Mahdi ◽  
Nadia Ghadhanfer Hikmat ◽  
Dalmn Yaseen Taha
Keyword(s):  
Electron Microscope ◽  
Powder Metallurgy ◽  
Optical Microscope ◽  
Ti Alloy ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alloy Properties ◽  
Ti Content ◽  
Scanning Electron

The effect of different Ti additions on the microstructure of Al-Ti alloy prepared by powder metallurgy was investigated. A certain amount of Ti (10wt%, 15wt%, and 20wt%) were added to aluminium and the tests like microhardness, density, scanning electron microscope (SEM), optical microscope (OM) and X-Ray Diffraction (XRD) were conducted to determine the influence of different Ti additives on the Al-Ti alloy properties and microstructure. The results show that the grains of α-Al changed from large grains to roughly spherical and then to small rounded grains with increasing Ti content, the micro-hardness of the alloy increases with increasing Ti, and XRD results confirm the formation of TiAl3 intermetallic compound during sintering.

Microstructure and Mechanical Properties of Ti-Al-Mo-V-Ta Alloys

2013 ◽  
Vol 785-786 ◽  
pp. 86-90
Author(s):  
D.H. Xiao ◽  
X.X. Li ◽  
X.Z. Wu ◽  
Dan Liu ◽  
Y.S. Zhang
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Relative Density ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alpha Beta ◽  
Hot Pressing Sintering ◽  
Scanning Electron

P/M Ti-Al-Mo-V-Ta alpha-beta alloys were processed by hot-pressing sintering technique. The effects of Ta additions on microstructure and properties of the Ti-5Al-4Mo-4V alloys were investigated using X-ray diffraction, optical microscope, scanning electron microscope and mechanical properties tests. The results show that minor Ta addition improves the relative density and the mechanical properties of P/M Ti-5Al-4Mo-4V alloys. After sintering for 4h at 1623 K, the relative density and compression strength of Ti-5Al-4Mo-4V-5Ta alloy are 99.3% and 1950 MPa.

Organoclay-reinforced polyethersulfone-modified epoxy-based hybrid nanocomposites

2011 ◽  
Vol 23 (7) ◽  
pp. 526-534 ◽  
Author(s):  
Yang Wang ◽  
Boming Zhang ◽  
Jinrui Ye
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Hybrid Nanocomposites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Modified Epoxy ◽  
Scanning Electron

Hybrid nanocomposites were successfully prepared by the incorporation of polyethersulfone (PES) and organoclay into epoxy resin. They had higher fracture toughness than the prepared PES/epoxy blend and organoclay/epoxy nanocomposites. The microstructures of the hybrid nanocomposites were studied. They were comprised of homogeneous PES/epoxy semi-interpenetrating network (semi-IPN) matrices and organoclay micro-agglomerates made up of tactoid-like regions composed of ordered exfoliated organoclay with various orientations. The former was confirmed with dynamic mechanical analysis, scanning electron microscopy and transmission electron microscopy, while the latter was successfully observed with X-ray diffraction measurements, optical microscope, scanning electron microscope and transmission electron microscope. The improvement of their fracture toughness was due to the synergistic toughening effect of the PES and the organoclay and related to their microstructures.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of Al2O3-TiC-ZrO2 Ceramic Composites

2012 ◽  
Vol 476-478 ◽  
pp. 1031-1035
Author(s):  
Wei Min Liu ◽  
Xing Ai ◽  
Jun Zhao ◽  
Yong Hui Zhou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Al2O3-TiC-ZrO2ceramic composites (ATZ) were fabricated by hot-pressed sintering. The phases and microstructure of the composites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relative density and mechanical properties (flexural strength, fracture toughness and Vicker’s hardness) of the composites were tested. The results show that the microstructure of the composites was the gray core-white rim. With the increase of sintering temperature, the relative density and mechanical properties of the composites increased first and then decreased. The composite sintered at 1705°C has the highest synthetical properties, and its relative density, flexural strength, fracture toughness and Vickers hardness are 98.3%,970MPa,6.0 MPa•m1/2and 20.5GPa, respectively.

Effect of Casting Overheat and Rolling Temperature on Morphology of Sulfide in 30MnVS Steel

2012 ◽  
Vol 457-458 ◽  
pp. 270-273
Author(s):  
Yi You Tu ◽  
Guo Zhong Li
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Continuous Casting ◽  
Optical Microscope ◽  
Rolling Temperature ◽  
Ferrite Content ◽  
Continuous Casting Slab ◽  
Intragranular Ferrite ◽  
Sulfide Segregation ◽  
Scanning Electron

Effect of superheat and initial rolling temperature on the morphology and distribution of sulfide in non quenched and tempered free cutting steel 30MnVS has been studied by optical microscope and scanning electron microscope. Results show that proper superheat and initial rolling temperature can turn rod-shaped sulfide into massive or globular sulfide，to alleviate sulfide segregation and pro-eutectoid ferrite distribution along the boundary of pearlite clusters in 30MnVS , increase the intragranular ferrite content and optimize the structure of continuous casting slab.

Analysis of an Axle Failure under Torsional Load

2016 ◽  
Vol 850 ◽  
pp. 101-106 ◽  
Author(s):  
Shu Mei Li ◽  
Jian Jun Yang ◽  
Wei Dong Zhang ◽  
August Chang ◽  
Cai Xia Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Failure Mechanism ◽  
Field Testing ◽  
Optical Microscope ◽  
Fatigue Lifetime ◽  
Torsional Load ◽  
Torsional Fatigue ◽  
Secondary Cracks ◽  
Scanning Electron

Premature fracture of an axle under torsional load occurred after a tracked military tank had experienced field testing for only 80 kilometers. Visual metallographic examinations were performed with optical microscope (OM) and scanning electron microscope (SEM). The investigation demonstrates that the premature fracture is caused by metallurgical problems inside the axle where the primary and secondary cracks originate, propagate, and eventually result in final catastrophic rupture through torsional fatigue. The failure mechanism is summarized and improvement of the fatigue lifetime for the axle is recommended.

scholarly journals Ferroelectromagnetic Properties of PbFe1/2Nb1/2O3 (PFN) Material Synthesized by Chemical-Wet Technology

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2504 ◽  
Author(s):  
Dariusz Bochenek ◽  
Przemysław Niemiec
Keyword(s):  
Magnetic Properties ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sintering Temperature ◽  
Closed Porosity ◽  
X Ray ◽  
Synthesis Conditions ◽  
Ceramic Samples ◽  
Sem Microstructure ◽  
Scanning Electron

In this work, PbFe1/2Nb1/2O3 (PFN) ceramic samples synthesized by chemically wet method (precipitation from the solution) were obtained. Due to the tendency to form powder agglomerates, the synthesized powder was subjected to ultrasound. The sintering was carried out under various technological conditions, mainly through controlling the sintering temperature. -X-ray powder-diffraction (XRD), scanning electron microscope (SEM) microstructure analysis, as well as the examinations of dielectric, ferroelectric, and magnetic properties of the PFN ceramics were carried out. Studies have shown that hard ceramic agglomerates can be partially minimized by ultrasound. Due to this treatment, closed porosity decreases, and the ceramic samples have a higher density. Optimization and improvement of the technological process of the PFN material extends the possibility of its use for the preparation of multiferroic composites or multicomponent solid solutions based on PFN. Such materials with functional properties find applications in microelectronic applications, e.g., in systems integrating ferroelectric and magnetic properties in one device. The optimal synthesis conditions of PFN ceramics were determined to be 1050 °C/2 h.

Study on the Properties of Doped La in BaBi4Ti4O15 Ceramic

2007 ◽  
Vol 26-28 ◽  
pp. 243-246
Author(s):  
Xing Hua Yang ◽  
Jin Liang Huang ◽  
Xiao Wang ◽  
Chun Wei Cui
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sintering Temperature ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lanthanum Content ◽  
Scanning Electron

BaBi4-xLaxTi4O15 (BBLT) ceramics were prepared by conventional solid phase sintering ceramics processing technology. The crystal structure and the microstructure were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD analyses show that La3+ ions doping did not change the crystal structure of BBT ceramics. The sintering temperature increased from 1120°C to 1150°C with increasing Lanthanum content from 0 to 0.5, but it widened the sintering temperature range from 20°C to 50°C and refined the grain size of the BBT ceramic. Additionally, polarization treatment was performed and finally piezoelectric property was measured. As a result, the piezoelectric constant d33 of the 0.1at.% doped BBLT ceramics reached its highest value about 22pc/N at polarizing electric field of 8kV/mm and polarizing temperature of 120°C for 30min.

Investigation on the Microstructure Hardness for the Hot Compressed Duplex Steel

2022 ◽  
Vol 905 ◽  
pp. 30-37
Author(s):  
Shu Lan Zhang ◽  
Xiao Dan Zhang ◽  
Hai Feng Xu ◽  
Chang Wang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Optical Microscope ◽  
Ferrite Phase ◽  
Ferrite Formation ◽  
Average Hardness ◽  
Duplex Steel ◽  
Quench Temperature ◽  
Fluctuation Range ◽  
Scanning Electron

Effect of microstructure size and type on the hardness for the duplex steel were disclosed by using of optical microscope (OM), scanning electron microscope (SEM) and nanoindenter for the samples hot compressed under different temperature with reduction of 10%, 30%, 50% and 70%. OM and SEM were used to measure the average martensite lamellar width, space and indenter morphology. nanoindenter test characterized the microstructure hardness for the samples under different process. Experiment results show that martensite hardness for the sample hot compressed at 950°C has larger diversity than that of sample hot compressed at 1200°C. The martensite hardness fluctuation range for the sample compressed at 950°C is almost from about 7GPa to 12GPa, while, for the sample compressed at 1200°C, the fluctuation range is basically from about 9GPa to 12GPa. However, the average hardness for the samples hot compressed at 950°C is comparably smaller, which is related with lower quench temperature. The larger martensite hardness fluctuation is mainly related with induced ferrite formation and finer martensite lamellar width. For the ferrite phase, the hardness fluctuation range is lower.

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