Needle Like Fe-Containing Intermetallic Compounds of High Silicon Aluminum Alloy with Fe Modified by Mn and Ultrasonic Vibration

2016 ◽  
Vol 879 ◽  
pp. 2286-2292 ◽  
Author(s):  
Gu Zhong ◽  
Shu Sen Wu ◽  
Chong Lin ◽  
Hiromi Nagaumi

In this study, the modification effects and mechanism of manganese (Mn) and ultrasonic vibration (USV) on the needle-like Fe-containing intermetallic compounds of Al-20Si-xFe-2.0Cu-0.4Mg-1.0Ni (x=1, 2 wt.%) alloy have been studied respectively. The effect of Fe-containing phases on volume fraction of hard phases is also investigated. The results show that the mechanism and effect of Fe-containing intermetallic compounds improved by Mn are in close relationship with Fe content. Mn can promote to form less harmful α-Al15(Fe,Mn)3Si2 phase, or replace some Fe atoms of β-Al5FeSi and δ-Al4FeSi2 according to different Fe content. When USV was applied to this alloy containing 2%Fe near liquidus temperature, most of the acicular β phases formed in traditional process are substituted by fine plate δ phases. With the combined effects of 0.5%Mn and USV, the acicular β phases are almost repressed and the Fe-containing phases exist in form of fine Al4(Fe,Mn)Si2 and Al5(Fe,Mn)Si particles about 20~30μm. Consequently, the total volume fraction of hard phases which are composed of primary silicon particles and Fe-containing phases increases significantly.

2014 ◽  
Vol 922 ◽  
pp. 638-644
Author(s):  
Meng Sha ◽  
Shu Sen Wu ◽  
Ping An ◽  
You Wu Mao

The combined effects of the Co addition and Ultrasonic Vibration (USV) on microstructure and properties of Al–20Si–2Cu–1Ni–0.6Mg alloy were studied in this paper. The volume fraction of Co-bearing intermetallic compounds was increased with the increasing of Co content when various levels of Co (from 0% to 1.5%) added respectively into the alloys whether they formed in traditional casting or with USV treatment. The Co-bearing compounds presented as Chinese script or granular when Co was equal or less than 0.7% and turned into dendritic or fish-bone shape when Co was more than 0.7%. USV treatment applied around liquidus temperature of the melt could lead to a refinement of Co-containing compounds by promoting nucleus formation, hindering preferential growth on certain direction, and enlarging solute diffusion coefficient. The addition of equal or less than 0.7% Co, as well as application of USV is very effective in promotion of tensile strength of the hypereutectic Al–Si alloys.


Author(s):  
F. J. Fraikor ◽  
A. W. Brewer

A number of investigators have examined moire patterns on precipitate particles in various age-hardening alloys. For example, Phillips has analyzed moire fringes at cobalt precipitates in copper and Von Heimendahl has reported on moire fringes in the system Al-Au. Recently, we have observed moire patterns on impurity precipitates in beryllium quenched in brine from 1000°C and aged at various temperatures in the range of 500-800°C. This heat treatment of beryllium rolled from vacuum cast ingots produces the precipitation of both an fee ternary phase, AlFeBe4, and an hcp binary phase, FeBe11. However, unlike a typical age-hardening alloy, the solute content of this material is low (less than 1000 ppm of Fe and 600 ppm of Al) and hence the total volume fraction of precipitates is small. Therefore there is some difficulty in distinguishing the precipitates and their orientation relationships with the beryllium matrix since the weak precipitate spots generally do not appear on the diffraction patterns.


2017 ◽  
Vol 24 (Supp02) ◽  
pp. 1850022
Author(s):  
MAOYUAN LI ◽  
LIN LU ◽  
ZHEN DAI ◽  
YIQIANG HONG ◽  
WEIWEI CHEN ◽  
...  

Amorphous Al–Cu–Ti metal foams were prepared by spark plasma sintering (SPS) process with the diameter of 10[Formula: see text]mm. The SPS process was conducted at the pressure of 200 and 300[Formula: see text]MPa with the temperature of 653–723[Formula: see text]K, respectively. NaCl was used as the space-holder, forming almost separated pores with the porosity of 65 vol%. The microstructure and mechanical behavior of the amorphous Al–Cu–Ti metal foams were systematically investigated. The results show that the crystallinity increased at elevated temperatures. The effect of pressure and holding time on the crystallization was almost negligible. The intermetallic compounds, i.e. Al–Ti, Al–Cu and Al–Cu–Ti were identified from X-ray diffraction (XRD) patterns. It was found that weak adhesion and brittle intermetallic compounds reduced the mechanical properties, while lower volume fraction and smaller size of NaCl powders improved the mechanical properties.


2015 ◽  
Vol 1095 ◽  
pp. 150-154
Author(s):  
Jian Zhang ◽  
Yang Li ◽  
Long Zhi Zhao ◽  
Ming Juan Zhao ◽  
Xian Jiang

In common hypereutectic high Si-Al alloy, the properties and applications of high Si-Al alloy was influenced by the thick multi-triangle shaped primary silicon seriously. In this paper, the fine hypereutectic Al-Si alloy was fabricated with ultrasonic vibration aided casting technology and the influence of ultrasonic vibration on the alloy structure is investigated as well as the influence of the silicon content on the wear volume and hardness with the comparison of microscopic structures. The results show that the increase of silicon content ascends the hardness of the high Si-Al alloy. However, along with increase of silicon content, the wear loss decreases initially and increases when the silicon content is larger than 22%.


2011 ◽  
Vol 299-300 ◽  
pp. 566-571
Author(s):  
Zuo Fu Zhao ◽  
Jian Zhong Wang ◽  
Jin Gang Qi ◽  
Shan Dai ◽  
Dong Jun Zhang

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.


MRS Bulletin ◽  
1995 ◽  
Vol 20 (8) ◽  
pp. 33-39 ◽  
Author(s):  
Morihiko Nakamura

More than 25 years have passed since Intermetallic Compounds, edited by Westbrook, was published. Since that time, enormous advances have been made in the understanding and usage of intermetallic compounds. It is known that intermetallic compounds are generally brittle. Thus, alloys that contain intermetallics may also be brittle. However, many intermetallic compounds are known to have extraordinary functions and characteristics that are not observed in ordinary metals and alloys. Thus, they function as magnetic materials, superconductors, semiconductors, hydrogen absorbing alloys, shape memory alloys, and so on.Many high-strength structural alloys like maraging steels and duralumins are strengthened by fine precipitates of intermetallic phases. Nickel-based superalloys, which are used for airplane-engine parts, contain 60-70% of Ni3Al-based intermetallics by volume fraction and exhibit high strength at high temperatures. Hard metals, which are used for cutting tools, are composed of a large amount of hard but brittle intermetallics like WC and a small amount of ductile cobalt. Intermetallic compounds like TiAl are also investigated for their applications as structural materials where high strength at high temperatures is required.In a strict sense, intermetallic compounds are composed of two or more metallic elements. In a wider sense, they are composed of metallic and/or semimetallic elements. Each is characterized by an ordered arrangement of two or more kinds of atoms, that is, the formation of a superlattice, and have various kinds of interatomic bonding, ranging from metallic to covalent or ionic bonding. The ordering of atoms and the strong interatomic bonding result in many attractive properties for intermetallic compounds.


2007 ◽  
Vol 561-565 ◽  
pp. 729-732 ◽  
Author(s):  
Gen Sasaki ◽  
Fumiaki Kondo ◽  
Kazuhiro Matsugi ◽  
Osamu Yanagisawa

Vapor grown carbon fiber (VGCF) was sleaved in acetone with ultrasonic vibration. Then pure aluminum powders with 3 μm in average diameter was poured into VGCF containing acetone and mixed with ultrasonic vibration. The composites were fabricated by electro spark sintering. The strength, rigidity, electrical conductivity and microstructure of the composites was investigated. VGCF was distributed uniformly and no pores was observed in composite. As increasing the volume fraction of VGCF in composites, the strength of composites increased gradually but the elongation decreased. The electrical resistivity of the composites increased as increasing VGCF content, constantly. The theoretical resistivity of composites without residual stress is lower than that of experimental results. It seems that is caused by the high dislocation density and strain introduced by big difference of thermal expansion between VGCF and pure aluminum.


2014 ◽  
Vol 1027 ◽  
pp. 48-51 ◽  
Author(s):  
Dao Hui Xiang ◽  
Yu Long Zhang ◽  
Guang Bin Yang ◽  
Song Liang ◽  
Yan Feng Wang ◽  
...  

High volume fraction SiCp/Al composites were grinded in rotary ultrasonic vibration aided grinding in this experiment, exploring the effects of different grinding parameters (grinding depth, grinding wheel speed, feed rate) on grinding force and the material removal mechanism with ultrasonic grinding. The results showed that grinding force of ultrasonic grinding is lower than the ordinary grinding in the same grinding parameters. Studying on material removal mechanism of ultrasonic vibration grinding is bound to have important theoretical and practical significance for the improvement of grinding processes and the development of mechanical according to the advantages of grinding and ultrasonic machining. Keywords: High volume fraction SiCp/Al composites; ultrasonic grinding; grinding force


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