Temperature Effect of Refining Performance by Al-Ti-B (C) Master Alloys

2011 ◽  
Vol 306-307 ◽  
pp. 475-480
Author(s):  
Cong Juan Gao ◽  
Hai Min Ding ◽  
Xiang Fa Liu

Refining performance and mechanism of Al-5Ti-1B and Al-5Ti-0.4C master alloys at different temperature were investigated in this paper. The experimental results show that the refining effect of Al-5Ti-0.4C master alloy becomes worse as temperature increasing from 750°C to 1200°C, The refining effect of Al-5Ti-1B master alloy becomes worse as temperature increasing from 750°C to 1000°C. However, when the temperature is above 1000°C, the refining effect of Al-5Ti-1B master alloy recovers gradually as temperature increasing. TiB2 particles with TiAl3 layers are the heterogeneous nucleating cores of α-Al at low temperature. However, TiB2 particles are the heterogeneous nuclei of α-Al at high temperature.

2012 ◽  
Vol 217-219 ◽  
pp. 377-381 ◽  
Author(s):  
Ying Long Li ◽  
Fu Rong Cao ◽  
Li Jin

The microstructural characters and refining property of Al-Ti-C grain refinement alloy prepared by ultrasound coupling method were studied by analytical means such as SEM, and the reaction synthesis mechanism of Al-Ti-C grain refinement was discussed. Experimental results show that the Al-Ti-C alloy refiner using “thermite reduction method” under high-energy ultrasound was prepared experimentally. Its microstructure character is that master alloy has smaller size of TiC, its quantities are larger and are dispersed. Melt reaction is generally that the source of titanium releases Ti atoms under high temperature of ultrasonic. Ti atoms react with aluminum to generate TiAl3, and react with carbon to generate TiC.


Author(s):  
Wenxue Fan ◽  
Hai Hao

Abstract Grain refinement has a significant influence on the improvement of mechanical properties of magnesium alloys. In this study, a series of Al–Ti–C-xGd (x = 0, 1, 2, 3) master alloys as grain refiners were prepared by self-propagating high-temperature synthesis. The synthesis mechanism of the Al–Ti–C-xGd master alloy was analyzed. The effects of Al–Ti–C-xGd master alloys on the grain refinement and mechanical properties of AZ31 (Mg-3Al-1Zn-0.4Mn) magnesium alloys were investigated. The results show that the microstructure of the Al–Ti–C-xGd alloy contains α-Al, TiAl3, TiC and the core–shell structure TiAl3/Ti2Al20Gd. The refining effect of the prepared Al–Ti–C–Gd master alloy is obviously better than that of Al–Ti–C master alloy. The grain size of AZ31 magnesium alloy was reduced from 323 μm to 72 μm when adding 1 wt.% Al–Ti–C-2Gd master alloy. In the same condition, the ultimate tensile strength and elongation of as-cast alloy were increased from 130 MPa, 7.9% to 207 MPa, 16.6% respectively.


1991 ◽  
Vol 219 ◽  
Author(s):  
Xing Chen ◽  
Upali Jayamaha ◽  
Chen-Yu Tai

ABSTRACTCharge transport in a-Si:H films is studied by measuring the intensity and the rate of decay of the transient photocurrent with optical bias illumination. The optical bias enhancement of the transient photocurrent due to the probe beam decreases at first as the temperature is decreased, reaches a minimum at about 21OK, and then increases as the temperature is further decreased. This observation, together with the decay time measurements, indicates a change in the mechanism of charge propagation from conduction band transport at high temperature to hopping conduction in the low temperature. A theory of hopping conduction in tail states is developed to explain the experimental results. A quantitative comparison of the theoretical and experimental results is made to determine the localization length of the tail states.


Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 310 ◽  
Author(s):  
Wanwu Ding ◽  
Taili Chen ◽  
Xiaoyan Zhao ◽  
Yan Cheng ◽  
Xiaoxiong Liu ◽  
...  

Al-Ti-C master alloys have been widely investigated by various researchers. However, their refining effectiveness is still severely compromised by the preparation process. In this work, the aluminum melt in-situ reaction was carried out to synthesize the Al-5Ti-0.62C, and its refining performance was estimated. The thermodynamics calculation and differential scanning calorimeter experiment were used to investigate the synthesis mechanism of TiC. Quenching experiment was conducted to explore phase and microstructure transformation of the Al-5Ti-0.62C system. The results show that the main phases of Al-5Ti-0.62C master alloys are α-Al, Al3Ti, and TiC and it has a positive effect on commercial pure aluminum refining. Commercial pure aluminum is completely refined into the fine equiaxed structure by adding 0.3% Al-5Ti-0.62C master alloy. TiC particles mainly distribute in the grain interior and grain boundaries. The excess Ti came from the dissolution of Al3Ti spreading around TiC and finally forming the Ti-rich zone to promote the nucleation of α-Al. The experiments certified that TiC was formed by the reaction between solid C and excess Ti atoms. The main reactions in the Al-5Ti-0.62C system were that solid Al is transferred into liquid Al, and then liquid Al reacted with solid Ti to form the Al3Ti. At last, the release of a lot of heat promotes the formation of TiC which formed by the Ti atoms and solid C.


Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 32 ◽  
Author(s):  
Byung Joo Kim ◽  
Sung Su Jung ◽  
Ji Hoon Hwang ◽  
Yong Ho Park ◽  
Young Cheol Lee

The modification effect of Al-5Ti-1B master alloy on eutectic Mg2Si in Al-Zn-Si-Mg system alloy was investigated in this study. The microstructure shows that an extreme effect can be achieved after the addition of Al-5Ti-1B master alloy into the base alloy. The morphology of eutectic Mg2Si changed from Chinese script to fine polygonal shape, and the size was refined from over 50 μm to under 10 μm. This morphology change is believed to be due to TiB2 particles existing in Al-5Ti-1B master alloy, and the presence of TiB2 particles inside the modified Mg2Si was confirmed by scanning electron microscope/energy dispersive spectrometer (SEM/EDS) observation. The mechanical properties were also improved by the addition of Al-5Ti-1B master alloys. This study investigated the reason for the improvement in mechanical properties with the modification of the microstructure.


2012 ◽  
Vol 562-564 ◽  
pp. 238-241
Author(s):  
Z.Q Wang ◽  
D.L Yang ◽  
Z.X Yang ◽  
H.R Geng

In this paper, two types of Zn-Al-Ti-B-C master alloys were produced by a two-step method and were found to have good refinement effect for Zn-50Al alloy. SEM results show that TiC and TiB2 particles act as the nucleating center of α-Al grains in Zn-50Al alloy. The presence of TiAl3-xZnx phase in the matrix of Zn-Al-Ti-B-C master alloy was found to further enhance the refinement effect. The melt thermal-rate treatment process present good grain refinement effect for Zn-50Al alloy and it was further promoted by the addition of Zn-Al-Ti-B-C master alloy into Zn-Al matrix.


2015 ◽  
Vol 5 (5) ◽  
pp. 2985-2993 ◽  
Author(s):  
Songjian Zhao ◽  
Zan Qu ◽  
Naiqiang Yan ◽  
Zhen Li ◽  
Haomiao Xu ◽  
...  

The mechanism of Hg0 oxidation over catalysts at low temperature and at high temperature.


Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6739
Author(s):  
Yanli Ma ◽  
Taili Chen ◽  
Lumin Gou ◽  
Wanwu Ding

The effects of CeO2 size on the microstructure and synthesis mechanism of Al-Ti-C alloy were investigated using a quenching experiment method. A scanning calorimetry experiment was used to investigate the synthesis mechanism of TiC, the aluminum melt in situ reaction was carried out to synthesize master alloys and its refining performance was estimated. The results show that the Al-Ti-C-Ce system is mainly composed of α-Al, Al3Ti, TiC and Ti2Al20Ce. The addition of CeO2 obviously speeds up the progress of the reaction, reduces the size of Al3Ti and TiC and lowers the formation temperature of second-phase particles. When the size of CeO2 is 2–4 μm, the promotion effect on the system is most obvious. The smaller the size of CeO2, the smaller the size of Al3Ti and TiC and the lower the formation temperature. Al-Ti-C-Ce master alloy has a significant refinement effect on commercial pure aluminum. When the CeO2 size is 2–4 μm, the grain size of commercial pure aluminum is refined to 227 μm by Al-Ti-C-Ce master alloy.


2020 ◽  
Vol 5 (1) ◽  
pp. 6-13
Author(s):  
Dhelvian Gading Primadhika ◽  
Parjiman ◽  
Djaohar Mochammad ◽  
Himma Firdaus

ABSTRACT The purpose of this research is to know about the effect of current rate increasing and ambient temperature change on tripping time miniature circuit breakers 6A type C. In this research using an experimental method approach with the quantitative method. The research subject used five samples new miniature circuit breakers produced by Asian and European brand. The research data collection is carried out by testing using PLN voltage source, linier load and temperature change on chamber to know five samples miniature circuit breakers characteristics tripping time refer to SPLN 108:1993. The research result showed that, current rate increasing to ± 2.55 In and ambient temperature change have an effect on five samples miniature circuit breakers characteristics tripping time, where on reference temperature, different characteristics tripping time for each other however were still within the standard limits SPLN 108:1993. Next on low temperature testing, five samples miniature circuit breakers have change tripping time to be slowed rather than reference temperature testing with deviation MCB A 1.75 until 497.90 second, MCB B 3.81 until 114.89 second, MCB C 2.04 second until 637.42 second, MCB D 0.33 until 1647.96 second, dan MCB E 2.89 until 234.49 second. Last on high temperature testing five samples miniature circuit breakers have change tripping time to be faster rather than reference temperature testing with deviation MCB A 2.63 until 396.93 second, MCB B 2.78 until 251.96 second, MCB C 5.79 second until 775.25 second, MCB D 8.27 until 339.49 second, dan MCB E 3.86 until 95.02 second. Based on this research result, each increase current rate flow through miniature circuit breakers, than miniature circuit breakers tripping time to be faster. When miniature circuit breakers was given low temperature effect, than miniature circuit breakers have change tripping time to be slowed rather than reference temperature. While miniature circuit breakers was given high temperature effect, than miniature circuit breakers have change tripping time to be faster rather than reference temperature.   ABSTRAK Tujuan dari penelitian ini adalah untuk mengetahui pengaruh kenaikan besar arus listrik yang disertai dengan perubahan suhu lingkungan terhadap waktu trip pada mini circuit breaker 6A Tipe C. Metode yang digunakan adalah metode eksperimen dengan pendekatan metode kuantitatif. Subjek penelitian yang akan diteliti adalah MCB yang dalam kondisi baru berjumlah 5 sampel produksi asia maupun eropa. Pengumpulan data penelitian dilakukan dengan pengujian menggunakan sumber tegangan PLN, beban linier dan perubahan suhu di chamber pengujian untuk mengetahui karakteristik waktu trip 5 MCB yang mengacu pada SPLN 108:1993. Hasil penelitian menunjukan bahwa, peningkatan besar arus hingga ±2.55 In dan perubahan suhu mempunyai pengaruh terhadap karakteristik waktu trip 5 sampel MCB, dimana pada suhu refrensi masing-masing memiliki perbedaan karakteristik waktu trip namun masih dalam batas standar SPLN 108:1993. Lalu pada pengujian dengan suhu rendah, 5 sampel MCB masing-masing mengalami perubahan waktu trip yang lebih lambat dari pengujian pada suhu refrensi dengan deviasi MCB A 1.75 hingga 497.90 detik, MCB B 3.81 hingga 114.89 detik, MCB C 2.04 detik hingga 637.42 detik, MCB D 0.33 hingga 1647.96 detik, dan MCB E 2.89 hingga 234.49 detik. Sedangkan pada pengujian dengan suhu tinggi 5 sampel MCB masing-masing mengalami perubahan waktu trip yang lebih cepat dari pengujian pada suhu refrensi dengan deviasi MCB A 2.63 hingga 396.93 detik, MCB B 2.78 hingga 251.96 detik, MCB C 5.79 detik hingga 775.25 detik, MCB D 8.27 hingga 339.49 detik, dan MCB E 3.86 hingga 95.02 detik. Dari hasil pengujian yang telah dilakukan di dapatkan hasil semakin besar arus yang melewati MCB maka akan lebih cepat MCB akan trip. Lalu dengan di beri pengaruh suhu rendah, maka MCB akan lebih lambat untuk trip. Sedangkan dengan di beri pengaruh suhu tinggi, maka MCB akan lebih cepat untuk trip.


2014 ◽  
Vol 494-495 ◽  
pp. 95-99
Author(s):  
Heng Jia Zhang ◽  
Bo Yang

This study constitutes an empirical fleet with electric vehicles (EV) and conventional vehicles (CV) which used by a large number of test participants who have different travel mileage to research the fuel-saving efficiency of EVs under daily travel mode within six months. Experimental results show that there is a great difference in energy consumption when EV running under different average temperatures and seasons. During summer (high temperature) and winter (low temperature) the energy consumption is bigger and the average electric consumption of 100-kilometer is 12.3 kWh/100km. The fuel-saving efficiency of EV in Tianjin empirical test is 66.7% and which is 74.8% in ten typical cities in China. EV has better fuel-saving effect in the whole country. The fuel-saving efficiency in working-days and rest-days is 80.3% and 42.2% respectively. EV has the best fuel-saving effect in working-days.


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