Effects of High Density Ultrasonic Field Coupling on the Microstructures and Properties of Al-Si Alloy

2011 ◽  
Vol 291-294 ◽  
pp. 1981-1988 ◽  
Author(s):  
Ying Long Li ◽  
Hua Ding ◽  
Fu Rong Cao
Keyword(s):  
Liquid Phase ◽  
Acoustic Streaming ◽  
Sound Intensity ◽  
Large Degree ◽  
Ultrasonic Field ◽  
High Density ◽  
Field Coupling ◽  
Cavitation Effect ◽  
Eutectic Si ◽  
Equiaxed Grains

The effects of high density ultrasonic field coupling on the microstructures and properties of Al-12Si alloy were investigated. It is shown that when the melt undergoes ultrasonic coupling processing prior to solidification, the nucleation rate of liquid phase can be raised to make α(Al) dendrite transform towards near equiaxed grains, the growth of Si phase is restrained and eutectic Si microstructure is refined due to acoustic streaming effect and thermal mechanism; When the melt undergoes ultrasonic coupling processing during the melt solidification, large degree of supercooling is produced in the liquid phase in the solidification interface front edge to reduce the critical radius of crystal nucleus and critical work of nucleation and break up, rupture by melting and refine the Si phase to improve obviously the strength of Al-12Si alloy due to its cavitation effect, acoustic streaming action and heat undulation; The crushing effect of ultrasonic coupling on Si phase occurs mainly during the crystallizing solidification and threshold sound intensity exists.

Research on Microstructure and Refining Performance of Al-Ti-C Grain Refiner Prepared by Ultrasonic Coupling

2021 ◽  
Vol 1033 ◽  
pp. 69-73
Author(s):  
Jing Wen Zhu ◽  
Jing Tao Zhao ◽  
Zong Ming Jiang ◽  
Ying Long Li
Keyword(s):  
Acoustic Streaming ◽  
Ultrasonic Field ◽  
Second Phase ◽  
Particle Phase ◽  
Grain Refiner ◽  
Cavitation Effect ◽  
Homogenous Distribution ◽  
The Matrix ◽  
Refining Performance ◽  
Refining Time

The application of ultrasonic field in the preparation of Al-Ti-C refiners can lead to the the homogenous distribution of the second phase TiAl3 and the particle phase TiC in the matrix, thus enhancing the refinement effect. In this paper, the Al-Ti-C grain refiner was successfully prepared by the ultrasonic coupling method, and its microstructure was observed. The prepared refiner was added to pure Al to verify the refining performance, and the refining mechanism was analyzed. The results indicate that the Al-Ti-C grain refiner prepared by ultrasonic field has excellent refining performance, which reduces the grain size of Al to 100 μm, and the optimum activation refining time is 3 min. The reason is that the morphology and size of the second phase TiAl3 and TiC in Al-Ti-C are changed by cavitation effect, acoustic streaming effect and thermal effect caused by high intensity ultrasonic, and the α-Al nucleates effectively under the synergistic of TiC and TiAl3 particles.

Template-Free Liquid-Phase Synthesis of High-Density CdS Nanowire Arrays on Conductive Glass

2009 ◽  
Vol 113 (4) ◽  
pp. 1615-1619 ◽  
Author(s):  
Woo-Chul Kwak ◽  
Tae Geun Kim ◽  
Wonjoo Lee ◽  
Sung-Hwan Han ◽  
Yun-Mo Sung
Keyword(s):  
Liquid Phase ◽  
High Density ◽  
Nanowire Arrays ◽  
Phase Synthesis ◽  
Cds Nanowire ◽  
Conductive Glass ◽  
Template Free

Effect of Electron Scavenger on the γ-Radiolysis of Gaseous Propane at High Densities

1973 ◽  
Vol 51 (23) ◽  
pp. 3966-3969 ◽  
Author(s):  
Masaru Nishikawa ◽  
Yoh-ichi Yamaguchi ◽  
Kazuo Fujita ◽  
Kazunori Kon ◽  
Tetsuro Okamoto
Keyword(s):  
Liquid Phase ◽  
Room Temperature ◽  
High Density ◽  
Hydrogen Formation ◽  
Electron Pairs ◽  
Electron Scavenger ◽  
Similar Decrease

Hydrogen formation from γ-radiolysis of gaseous propane at 120 ± 1 °C was studied as the function of density in the range from 0.1 to 0.5 g/ml. G(H2) gradually decreased with density from 8.0 at 0.12 g/ml towards the liquid-phase value of 6.4 at room temperature. G(H2) in the presence of SF6 showed similar decrease from 3.9 to 3.0. The decrease was discussed in comparison to the abrupt drop in G-values from the radiolysis of ammonia at high density (11). The separation distances of ion–electron pairs were estimated from the analysis of the electron scavenging reaction.

Influence of Cooling Rate on Microstructure of Self-Reactive Spray Formed Ti(C,N)-TiB2 Composite Ceramic Preforms

2013 ◽  
Vol 631-632 ◽  
pp. 348-353 ◽  
Author(s):  
Hong Wei Liu ◽  
Jian Jiang Wang ◽  
Xiao Feng Sun ◽  
Ji Qiu
Keyword(s):  
Finite Element Method ◽  
Cooling Rate ◽  
Large Degree ◽  
Composite Ceramic ◽  
Diameter Ratio ◽  
Cooling Rates ◽  
Forming Technology ◽  
Liquid Phases ◽  
Equiaxed Grains ◽  
Remaining Time

With graphite, 45 steel and copper as substrates respectively, Ti(C,N)-TiB2 composite ceramic preforms with micro/nanometric grains were prepared by self-reactive sprayed forming technology. The cooling rate of spray particles deposited on different substrates was calculated by finite element method. The influence of cooling rate on morphology of micro/nanometric grains of Ti(C,N)-TiB2 composite ceramic preforms was studied by means of SEM, XRD and EDS. The results showed that the average cooling rates of particles deposited on the three kinds of substrates were 7.0×107°C/s, 8.1×107°C/s and 10.7×107°C/s respectively. The extremely quick cooling rate was the essential reason why the spray formed preforms were composed of micro/nanometric grains. The TiC0.3N0.7 grains in preforms deposited on three kinds of substrates all took on anomalous equiaxed grains. Quicker the cooling rates of the deposited particles were, smaller the grains were. The grain size of them was all less than 3μm. Whereas the influence of cooling rate on the morphology of the TiB2 grains was great. When with graphite as substrate, TiB2 took on rod-like grains with big length to diameter ratio. When with 45 steel as substrate, it took on near equiaxed grains. And when with copper as substrate, it took on lamina grains with thickness of about 100nm due to the extremely quick cooling rate and the extremely large degree of supercooling. That’s because with the change of the cooling rates, the remaining time of the liquid phases is different, so as to the growing time of the grains along the habit plane is also very different.

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