Effect of Titanium on Homogenizing Process and Microstructure of Alloy 2618

2014 ◽  
Vol 33 (3) ◽  
pp. 261-267 ◽  
Author(s):  
Tingting Liu ◽  
Ya Liu ◽  
Xuping Su ◽  
Haoping Peng ◽  
Jianhua Wang

AbstractThe effect of titanium on the homogenizing process of alloy 2618 and the microstructure of the Ti-containing alloy before and after homogenization has been investigated using optical microscope (OM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), differential thermal analysis (DTA). The results show that the addition of 1.5 mass% Ti to alloy 2618 could refine its grain size remarkably. A large amount of rod-shape Al3Ti particles with the size range of 2–12 μm distribute evenly and dispersively in the alloy. It is θ (Al2Cu) phase instead of S' (Al2CuMg) obtained in eutectic structures due to the non-equilibrium solidification in casting of 2618-Ti alloy, which is the same as alloy 2618. The optimal homogenization temperature (773 K) for Ti-containing alloy 2618 (2618-Ti alloy) is the same as that of alloy 2618. Combining the results of kinetic analysis and experiments, the optimized homogenizing time for Ti-containing alloy 2618 at 773 K is only 12 h, which is shorter than that for alloy 2618. The shortening of the optimized homogenizing time results mainly from the decrease of the grain size of 2618-Ti alloy.

2020 ◽  
Vol 26 (6) ◽  
pp. 132-139
Author(s):  
Sahib Mohammed Mahdi ◽  
Nadia Ghadhanfer Hikmat ◽  
Dalmn Yaseen Taha

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.


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Liu Liu ◽  
Decai Gong ◽  
Zhengquan Yao ◽  
Liangjie Xu ◽  
Zhanyun Zhu ◽  
...  

Abstract Historically, sutras played an important role in spreading Buddhist faith and doctrine, and today these remain important records of Buddhist thought and culture. A Mahamayuri Vidyarajni Sutra with polychrome paintings was found inside the cavity on top of the Nanmen Buddhist pagoda, built in the early Tang dynasty (618–627 CE) and located in Anhui Province, China. Textile was found on the preface which is strongly degraded and fragile. Unfortunately, the whole sutra is under severe degradation and is incomplete. Technical analysis based on scientific methods will benefits the conservation of the sutra. Optical microscopy (OM), micro-Raman spectroscopy combined with optical microscope (Raman), scanning electron microscopy in combination with energy dispersive X-ray analysis (SEM–EDS) and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterize the pigment and gilded material, as well as the paper fiber and textile. Pigments such as cinnabar, minium, paratacamite, azurite, lead white were found. Gilded material was identified as gold. A five-heddle warp satin, made of silk, was found as the textile on the preface of the sutra. The sutra’s preface and inner pages were made of paper comprised of bamboo and bark. As a magnificent yet recondite treasure of Buddhism, the sutra was analyzed for a better understanding of the material. A conservation project of the sutra will be scheduled accordingly.


2013 ◽  
Vol 281 ◽  
pp. 475-479
Author(s):  
Bo Wang ◽  
Quan Xi Cao ◽  
Guang Xu ◽  
Sen Tian

1.0at% Nd:YAG polycrystalline ceramics were sintered at 1420°C, 1500°C, 1600°C and 1730°C respectively by different heating rate (1°C/min and 5°C/min). The crystal structures were indexed by X-ray diffractometer (XRD). The microstructure and the grain size of the samples were characterized by scanning electron microscope (SEM). The optical transmittance spectra of the samples were measured using V-570 UV spectrophotometer. The sintering process of Nd:YAG ceramics and the effect of heating rate on the microstructure of samples have been investigated.


2012 ◽  
Vol 496 ◽  
pp. 379-382
Author(s):  
Rui Song Yang ◽  
Ming Tian Li ◽  
Chun Hai Liu ◽  
Xue Jun Cui ◽  
Yong Zhong Jin

The Cu0.81Ni0.19 has been synthesized directly from elemental powder of nickel and copper by mechanical alloying. The alloyed Cu0.81Ni0.19 alloy powders are prepared by milling of 8h. The grain size calculated by Scherrer equation of the NiCu alloy decreased with the increasing of milling time. The end-product was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM)


2007 ◽  
Vol 26-28 ◽  
pp. 243-246
Author(s):  
Xing Hua Yang ◽  
Jin Liang Huang ◽  
Xiao Wang ◽  
Chun Wei Cui

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.


2018 ◽  
Vol 281 ◽  
pp. 156-162
Author(s):  
Wang Nian Zhang ◽  
Xi Tang Wang ◽  
Zhou Fu Wang

The influence of the light burning temperature on the sintering property of nature dolomite has been investigated by two-step sintering process in the temperature range 1500 °C to 1600 °C. The resulting bulk densities and apparent porosities of the sintered dolomite samples were examined, and analyzing the sintered dolomite by scanning electron microscopy and X-ray diffraction were performed. The results showed light burned at 850 °C for 3 h, the main phases of the dolomite with 3-5 grain size were MgO, CaO and little CaCO3, and then fired at 1600 °C,the density of sintering dolomite reached to 3.38 g/cm3, the apparent property was 1.2 %, the size of MgO grain up to 3.75 μm . However when dolomite light burned at 1050 °C for 3 h, the main phases were MgO and CaO, and then fired at 1600 °C,the density of sintering dolomite only was 3.30 g/cm3, the apparent property was 2.3 %, the size of MgO only was 3.05 μm .


2018 ◽  
Vol 281 ◽  
pp. 230-235
Author(s):  
Wang Nian Zhang ◽  
Li Wang ◽  
Ni Deng

Micropowder MgCO3 was added into magnesite as raw materials to prepare magnesia using a two-step calcination method. The sample magnesite was characterized use X-ray diffraction (XRD) and scanning electron microscopy (SEM). Experimental results showed that the sample insulated at 1600° C for 3 hours before and after sintering presented a linear change rate of 15.6 % in the case of without adding micropowder MgCO3, the prepared magnesia had a bulk density of 2.31 g/cm3 and apparent porosity of 32.8 %, while MgO grain size was 3.11 μm. In the case of adding 8 % micropowder MgCO3, the sample magnesite before and after sintering showed a linear change rate of 17.9 %. The bulk density, apparent porosity of prepared magnesia were 2.46 g/cm3 and 28.1 % respectively, while the grain size of MgO was 5.15 mm.


Fibers ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 52 ◽  
Author(s):  
Oliviero Baietto ◽  
Mariangela Diano ◽  
Giovanna Zanetti ◽  
Paola Marini

The main objective of this work is the evaluation of the morphology change in tremolite particles before and after a grinding process. The crushing action simulates anthropic alteration of the rock, such as excavation in rocks containing tremolite during a tunneling operation. The crystallization habit of these amphibolic minerals can exert hazardous effects on humans. The investigated amphibolic minerals are four tremolite samples, from the Piedmont and Aosta Valley regions, with different crystallization habits. The habits can be described as asbestiform (fibrous) for longer and thinner fibers and non-asbestiform (prismatic) for prismatic fragments, also known as “cleavage” fragments. In order to identify the morphological variation before and after the grinding, both a phase contrast optical microscope (PCOM) and a scanning electron microscope (SEM) were used. The identification procedure for fibrous and prismatic elements is related to a dimensional parameter (length–diameter ratio) defined by the Health and Safety Executive. The results highlight how mineral comminution leads to a rise of prismatic fragments and, therefore, to a potentially safer situation for worker and inhabitants.


2013 ◽  
Vol 747-748 ◽  
pp. 765-771 ◽  
Author(s):  
Jian Sheng Yao ◽  
Ding Zhong Tang ◽  
Xiao Guang Liu ◽  
Cheng Bo Xiao ◽  
Xin Li ◽  
...  

The interfacial reactions between ceramic moulds and DZ417G and DZ125 superalloys were investigated. The microstructure and composition of the interface region were observed by optical microscope, X-ray diffraction and scanning electron microscope with energy dispersive spectroscopy. The results showed that (Al1-xCrx)2O3solid solution phase with pink color was formed from the dissolution of Cr2O3and Al2O3and vapour phase, which was transferred to the reaction surfaces. The reaction layer thicknesses of DZ417G and DZ125 alloys were about in the range of 40-50μm. The interface reaction product between DZ417G alloy and ceramic mould was TiO2and the product between DZ125 alloy and ceramic mould was HfO2.


2011 ◽  
Vol 686 ◽  
pp. 348-354 ◽  
Author(s):  
Shu Tao Xiong ◽  
Fu Sheng Pan ◽  
Bin Jiang ◽  
Xiao Ke Li

In the present work, Al-Ca metallic compound was prepared in Mg-Ca alloys and the effects of Al-Ca metallic compound and different Al/Ca values on the grain refinement of Mg-Ca alloys were investigated by scanning electron microscopy and X-ray diffraction, and the mechanism of grain refinement of Mg-Ca alloys was discussed. The results showed that the grain size of Mg-0.5Ca alloy was obviously reduced from 550μm to 230μm due to the addition of Al. Al2Ca phase existed in these alloys and its morphology evolved from granular to rod-like. It is regarded as the main factor for the grain refinement.


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