Study on the Influence of Different Pulse Temperatures on Al-22%Si Alloy Solidification Structure

2011 ◽  
Vol 299-300 ◽  
pp. 566-571
Author(s):  
Zuo Fu Zhao ◽  
Jian Zhong Wang ◽  
Jin Gang Qi ◽  
Shan Dai ◽  
Dong Jun Zhang
Keyword(s):  
Volume Fraction ◽  
Electric Pulse ◽  
Primary Silicon ◽  
Electrical Pulse ◽  
Solidification Structure ◽  
Alloy Solidification ◽  
Modification Effect ◽  
Electric Pulse Modification ◽  
Average Size

Taking the hypereutectic Al-Si alloy as the research object, the fading characteristics of Al-22% Si alloy at different pulse temperatures are investigated in this paper in order to analyze the mechanism of electrical pulse modification to the alloy. We can get the conclusion by observing the microstructure of the sample, measuring the microhardness and calculating the volume fraction and the average size of primary silicon: at different pulse temperatures, the effect of electric pulse modification is fading with static duration prolonging; meanwhile, with the temperature upward, the modification effect and fading trends to be weak, which indicates the best pulse temperature is one of the important factors to influence the modification effect.

Effects of Electric Pulse Modification on As-Cast Texture of Pure Copper

2010 ◽  
Vol 29-32 ◽  
pp. 1894-1897
Author(s):  
Jin Gang Qi ◽  
Jian Zhong Wang ◽  
Xing Jiang Liu ◽  
Shan Dai
Keyword(s):  
Volume Fraction ◽  
Vertical Section ◽  
Electric Pulse ◽  
Pure Copper ◽  
Solidification Structure ◽  
Crystal Direction ◽  
Ingot Axis ◽  
Maximum Value ◽  
Typical Type ◽  
Orientation Density

The modification of liquid metal by electric pulse (EP or EPM) is a novel method for improvement of solidification structure. In this study, the as-cast texture of EP-modified pure copper was investigated by using X-ray Schulz backscattered method. The experimental results show that the as-cast texture of EP-modified pure copper is dissimilar with that of the unmodified. The unmodified mainly exhibits a type of {110}<001> texture, and the maximum value of orientation density is 10.07, in the plane that parallel to the vertical section along the ingot axis, the <110> crystal direction has the most volume fraction of 27.18%; By contrast, the as-cast texture of EP-modified pure copper shows a typical type of {102}<001>, and the maximum value of orientation density is 12.88, at the same time, the corresponding <102> crystal direction changes to be the most volume fraction and its value is 22.82%. These facts indicate that the crystal orientation (texture) of solidification structure could be altered by EPM, and EPM technology would thus influence the following metal formability.

Influences of Acting Parameters of Electric Pulse Modification on the Al-22%Si-1.5%Cu Alloy

2011 ◽  
Vol 299-300 ◽  
pp. 233-237
Author(s):  
Li Jia He ◽  
Jian Zhong Wang ◽  
Jin Gang Qi ◽  
Hui Ling Du ◽  
Xing Jiang Liu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Electric Pulse ◽  
Solidification Structure ◽  
Cooling Curve ◽  
Pulse Treatment ◽  
Cu Alloy ◽  
Resistance Property ◽  
Structural Applications ◽  
Electric Pulse Modification ◽  
Electric Pulse Treatment

Hypereutectic Al-Si alloy are desirable and promising for many structural applications. The influences of electric pulse parameters on Al-22%Si-1.5%Cu alloy by using OM (optical microscope) analysis along with wear test had been investigated. This work focused on studying the comparison of its solidification structure and wear resistance property with and without electric pulse treatment, respectively. The results indicated that EPM (electric pulse modification) treatment with different voltage parameters along with the frequency parameters both had the remarkable effects on micro-structure, and the grain size of alloy was refined gradually with the increase of pulse voltage or frequency. The wear resistance property of the alloy was enhanced by electric pulse treatment. It was observed from DSC cooling curve that the precipitation peak point of primary silicon was delayed by electric pulse modification comparing to the original sample without electric pulse treatment, which was analyzed to play a critical key in the alloy grain refinement.

Investigation on the Primary Si Phase Solidification and the Properties of SiCw/Al-18Si Composites

2007 ◽  
Vol 353-358 ◽  
pp. 1275-1278
Author(s):  
Lin Geng ◽  
Hong Mei Wei ◽  
Xue Xi Zhang
Keyword(s):  
Squeeze Casting ◽  
Volume Fraction ◽  
Primary Silicon ◽  
Solidification Behavior ◽  
Scanning Calorimetry ◽  
Solidification Temperature ◽  
Casting Technique ◽  
Microstructure Observation ◽  
Primary Si ◽  
Average Size

SiCw/Al-18Si composites were prepared by squeeze casting technique. SiCw/Al-18Si composites were remelted before solidification. The effects of volume fraction of SiC whisker on solidification behavior of SiCw/Al-18Si composites were investigated by means of differential scanning calorimetry (DSC) technique and microstructure observation. DSC results indicated that the start solidification temperature and primary silicon peak temperature decreased gradually and the degree of supercooling increased with the increasing of SiC whisker content. SiC whisker and Sr decreased the average size of Si phases and improved the mechanical properties of the composites.

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

scholarly journals High Bending Strength Hypereutectic Al-22Si-0.2Fe-0.1Cu-Re Alloy Fabricated by Selective Laser Melting

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 528
Author(s):  
Chunyue Yin ◽  
Zhehao Lu ◽  
Xianshun Wei ◽  
Biao Yan ◽  
Pengfei Yan
Keyword(s):  
Selective Laser Melting ◽  
Bending Strength ◽  
Primary Silicon ◽  
Processing Parameters ◽  
Powder Materials ◽  
Laser Melting ◽  
Maximum Value ◽  
Fine Microstructure ◽  
Average Size ◽  
Al Matrix

The objective of the study is to investigate the corresponding microstructure and mechanical properties, especially bending strength, of the hypereutectic Al-Si alloy processed by selective laser melting (SLM). Almost dense Al-22Si-0.2Fe-0.1Cu-Re alloy is fabricated from a novel type of powder materials with optimized processing parameters. Phase analysis of such Al-22Si-0.2Fe-0.1Cu-Re alloy shows that the solubility of Si in Al matrix increases significantly. The fine microstructure can be observed, divided into three zones: fine zones, coarse zones, and heat-affected zones (HAZs). Fine zones are directly generated from the liquid phase with the characteristic of petaloid structures and bulk Al-Si eutectic. Due to the fine microstructure induced by the rapid cooling rate of SLM, the primary silicon presents a minimum average size of ~0.5 μm in fine zones, significantly smaller than that in the conventional produced hypereutectic samples. Moreover, the maximum value of Vickers hardness reaches ~170 HV0.2, and bending strength increases to 687.70 MPa for the as-built Al-22Si-0.2Fe-0.1Cu-Re alloys parts, which is much higher than that of cast counterparts. The formation mechanism of this fine microstructure and the enhancement reasons of bending strength are also discussed.

scholarly journals Effects of Polydispersity on the Phase Behavior of Additive Hard Spheres in Solution

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1543
Author(s):  
Luka Sturtewagen ◽  
Erik van der Linden
Keyword(s):  
Phase Behavior ◽  
Critical Point ◽  
Volume Fraction ◽  
Hard Spheres ◽  
Second Virial Coefficient ◽  
Two Phase ◽  
Different Types ◽  
Asymmetric Partitioning ◽  
Average Size ◽  
Liquid Liquid Phase Separation

The ability to separate enzymes, nucleic acids, cells, and viruses is an important asset in life sciences. This can be realised by using their spontaneous asymmetric partitioning over two macromolecular aqueous phases in equilibrium with one another. Such phases can already form while mixing two different types of macromolecules in water. We investigate the effect of polydispersity of the macromolecules on the two-phase formation. We study theoretically the phase behavior of a model polydisperse system: an asymmetric binary mixture of hard spheres, of which the smaller component is monodisperse and the larger component is polydisperse. The interactions are modelled in terms of the second virial coefficient and are assumed to be additive hard sphere interactions. The polydisperse component is subdivided into sub-components and has an average size ten times the size of the monodisperse component. We calculate the theoretical liquid–liquid phase separation boundary (the binodal), the critical point, and the spinodal. We vary the distribution of the polydisperse component in terms of skewness, modality, polydispersity, and number of sub-components. We compare the phase behavior of the polydisperse mixtures with their concomittant monodisperse mixtures. We find that the largest species in the larger (polydisperse) component causes the largest shift in the position of the phase boundary, critical point, and spinodal compared to the binary monodisperse binary mixtures. The polydisperse component also shows fractionation. The smaller species of the polydisperse component favor the phase enriched in the smaller component. This phase also has a higher-volume fraction compared to the monodisperse mixture.

Shape Memory Characteristics and Superelasticity of Ti-Ni-Cu Alloy Ribbons with Nano Ti2Ni Particles

2008 ◽  
Vol 8 (2) ◽  
pp. 722-727 ◽  
Author(s):  
Tae-hyun Nam ◽  
Cheol-am Yu ◽  
Jung-min Nam ◽  
Hyun-gon Kim ◽  
Yeon-wook Kim
Keyword(s):  
Melt Spinning ◽  
Volume Fraction ◽  
Deformation Behaviour ◽  
Parent Phase ◽  
Tensile Tests ◽  
Constant Load ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Average Size ◽  
Memory Characteristics

Microstructures and deformation behaviour of Ti-45Ni-5Cu and Ti-46Ni-5Cu alloy ribbons prepared by melt spinning were investigated by transmission electron microscopy, thermal cycling tests under constant load and tensile tests. Spherical Ti2Ni particles coherent with the B2 parent phase were observed in the alloy ribbons when the melt spinning temperature was higher than 1773 K. Average size of Ti2Ni particles in the ribbons obtained at 1873 K was 8 nm, which was smaller than that (10 nm) in the ribbons obtained at 1773 K. Volume fraction of Ti2Ni phase in the ribbons obtained at 1873 K was 40%, which was larger than that (20%) in the ribbons obtained at 1773 K. The stress required at temperatures of Af + 10 K for the stress-induced martensitic transformation increased from 93 MPa to 229 MPa and apparent elastic modulus of the B2 parent phase increased from 56 GPa to 250 GPa with increasing the melt spinning temperature from 1673 K to 1873 K in Ti-45Ni-5Cu alloy ribbons. The critical stress for slip deformation of the ribbons increased by coherent Ti2Ni particles, and thus residual elongation did not occur even at 160 MPa, while considerable plastic deformation occurred at 60 MPa in the ribbons without Ti2Ni particles. Almost perfect superelastic recovery was found in the ribbons with coherent Ti2Ni particles, while only partial superelastic recovery was observed in the ribbons without coherent Ti2Ni particles.

scholarly journals Effect of Electric Pulse Treatment on Hot-Dip Aluminizing Coating of Ductile Iron

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7219
Author(s):  
Jie Dong ◽  
Shouqian Yuan ◽  
Yongtao Sun ◽  
Shuangping Yang ◽  
Xiangdong Xing ◽  
...  
Keyword(s):  
Cast Iron ◽  
Electric Pulse ◽  
Liquid Aluminum ◽  
Interface Reaction ◽  
Nodular Cast Iron ◽  
Alloy Layer ◽  
Solidification Structure ◽  
Pulse Treatment ◽  
Treated Sample ◽  
Electric Pulse Treatment

In this paper, hot-dip aluminizing of ferrite nodular cast iron was carried out after treating liquid aluminum with different electrical pulse parameters. Compared with that of conventional hot-dip aluminizing, the coating structure of the treated sample did not change, the surface was smooth and continuous, and the solidification structure was more uniform. When high voltage and large capacitance were used to treat the liquid aluminum, the thickness and compactness of the coating surface layer increased. The thickness of the alloy layer decreased, and, the compactness and the micro hardness increased, so the electric pulse had a certain inhibition on the formation of the alloy layer. The growth kinetics of the alloy layer showed that the rate-time index decreased from 0.60 for the conventional sample to 0.38 for the electric pulse treated sample. The growth of the alloy layer was controlled by diffusion and interface reaction, but only by diffusion. The AC impedance and polarization curves of the coating showed that the corrosion resistance of hot-dip coating on nodular cast iron was improved by electric pulse treatment.

Heredity of Aluminum Melt by Electric Pulse Modification (II)

2007 ◽  
Vol 14 (5) ◽  
pp. 76-78 ◽  
Author(s):  
Jin-gang Qi ◽  
Jian-zhong Wang ◽  
Hui-ling Du ◽  
Li-yun Cao
Keyword(s):  
Electric Pulse ◽  
Aluminum Melt ◽  
Electric Pulse Modification

Experimental Studying Nanofluid Thermal Transfer In Microchannel

2016 ◽  
Vol 11 (2) ◽  
pp. 5-11
Author(s):  
Vladimir Aniskin ◽  
Valeriy Rudyak
Keyword(s):  
Silicon Dioxide ◽  
Transfer Coefficient ◽  
Volume Fraction ◽  
Micro Channel ◽  
Thermal Transfer ◽  
Nanoparticles Volume Fraction ◽  
Inner Diameter ◽  
Average Size ◽  
Silicon Dioxide Nanoparticle ◽  
Base Liquid

In paper new setup for studying the thermal transfer of nanofluid in the steel micro-channel with inner diameter 358 microns is described. Setup testing carried out by means of known experimental data about thermal transport of the water. Then the data about the thermal tranfer coefficient of the water based nanofluids with silicon dioxide nanoparticle with average size 25 nm are discussed. It was shown that nanofluids have the thermal transfer coefficient much more than that of base liquid. The enhancement of the thermal transfer coefficient of one-percent nanofluid is about 60 %. This enhancement grows with increasing of the nanoparticles volume fraction and flow rate of the nanofluid.

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