Effect of Zr on Microstructure of Near-eutectic AlSi Casting Alloys Modified by Sr

Influence of Journal of Southeast University (Natural Science Edition) on microstructure of 8 metamorphic near eutectic 1 cast alloys Sun Yu, Han Hengcheng, Sun Guoxiong, Yancheng Institute of Technology, Yancheng 224002, China) Department of Mechanical Engineering, Southeast University. Nanjing 210096 turned into a fibrous 纟3. However, it also promotes the formation of long trait dendrites. In order to suppress the formation of long columnar dendrites, this study used metallographic microscopy and scanning electron microscopy to analyze the effect of 31. metamorphic near eutectic 15 casting alloy structure. The results show that, with the increase in the amount of doping, dendrite; admitted that there is an equiaxed trend, the length of the trunk of the long columnar dendrite shortened, and there is no significant effect on the morphological size of eutectic silicon, when the amount added is 050.6, The dendrite is completely isometric. This is due to the formation of 21 颗粒 particles in the melt. In the alloy solidification process, alloys with near eutectic composition have excellent casting properties, good mechanical properties, corrosion resistance and weldability, and low expansion. Factors such as the mechanical industry car industry, provincial festivals and other fields have a wide range of applications. (1) In addition to the necessary degassing refining and modification, the alloying structure refinement and heat treatment strengthening are the main strengthening measures for this type of alloy, in which the microstructure refines the foot. Change; an important reason for the toughness of the alloy 2. Injury of the person 1 is often used as a grain refiner in industrial pure Lu and wrong alloys to obtain fine equiaxed crystals. However, in the case of one base alloy with a near eutectic composition, the study in Document 3 shows that when the amount of 151 added exceeds 8, it weakens. The effect of metamorphism is that the number of dendrites decreases, the primary silicon reappears, and the size of the cocrystals grows. Widely used in deformed aluminum alloys, its main role is to refine the crystal grains of solid solution and increase the recrystallization temperature. It distributes dispersed particles in the grain and on the grain boundary, and plays a role in pinning but in the casting alloy The application has not been reported. The metamorphism of the near eutectic composition 13 alloy 31 can make the primary silicon disappear and the eutectic silicon transform into a fine and uniform fibrous shape, but at the same time it leads to the formation of long columnar dendrites. Under the condition of non-equilibrium solidification in the form of three particles, it is expected to play the role of heterogeneous nucleation refinement organization. The main purpose of this study was to understand and observe the effects of 21. addition of alloy 1.6 on the as-cast microstructure of your alloy.

1 experimental method of financial accounting for gold, people say 0 intervening gold, and its 7 elements 1 meaning. And 1. Join 2 in the form of master alloys 01 and 14 respectively! The amount of addition is detailed 2. In the electric resistance furnace, graphite crucible is used for melting refining and degassing, and the metal type is preheated 250 and poured. The sample was eroded in the aqueous solution with a volume fraction of 5, and the microstructure was observed and recorded with an optical microscope and a scanning electron microscope. The composition of the particle phase was analyzed with 0.

2 Experimental results The morphology of the dendrite changes with the increase in the amount of 21. The details are as follows: 1.

Comparing 13 and 1.8, 1.6, and 0.221 in the alloy, the dendritic shape has no obvious change, and the dendrite is still a long columnar crystal. When the amount of 21 is 3, the dendrite has obvious tendency to equiaxed. The length of the main trunk was reduced and the second arm was thicker, indicating that the trunk and the second arm of the dendrite grew to be equivalence, with equivalence 1; when the adding amount was 4, the isometric trend was improved and the length of the trunk was greatly shortened by 1; When 21.

When the addition amount is 0.5, the long columnar crystals become completely isometric, and the main trunk completely disappears, and it grows in the form of a chrysanthemum toward the periphery. When the addition amount is 0.6, the dendrite becomes smaller in one step. However, the extent of its refinement did not clearly explain the changes in the Court. When the addition amount of Mingdan 21 is 0.50.6, the dendrite refinement effect is better. From the change of morphology and size of dendrites, the dendrites in the 1.69 alloy were refined and the dendrites were transformed from long columnar crystals to isometric products. This will help the corpse to improve the strength of the 13 cast alloys.

Progressive observation 21 added metal alloy photographs of 5 alloys. As a result, it was found that part of the dendrite had a polygonal, round, short-grained particle phase 2 with a size of about 50. The outer layer is covered with a light shell, and Wei Jiana, with a plethora of irritants, is very vicious (4). When discussing the atom fraction of the refinement behavior of dendrite 1, when an intermediate alloy is added to 1.631, it is The influence of crystal growth behavior 1 can be determined by the wealth of 1 and 7 continents; the fraction is 1; the maximum solubility of the primordial phase at the inlet is 0.5, and the +2,130 at 933.5 1 occurs; peritectic reaction. Its temperature is higher than the liquidus temperature of the alloy 1.63. 1. The theory of peritectic reaction based on grain refinement 6B13 is likely to serve as a nucleation base for the primary crystal. Although 2 Can is a square lattice, its crystal lattice is usually liquid, and its volume is similar to or proportional to the mass fraction of the lattice constant of Human 1 = 4.05, 10. References 5 and 8 describe the formation of a crystalline nucleus of human 1 under cold conditions, and there is a unique epitaxial relationship between the degree of mismatch, and therefore, the heart and granule 1 serve as the crystallization core of the branch product 1 .

The species to be kept in the form of seedlings is the solid solution in the sulcus and the other is the formation of the fact that the addition is relatively low when it is roughly determined to be 213. The particle phase contains a small number of 8 authors that may be presumably due to the electron beam. Drift or nucleus particle phase caused; In addition, the literature 5 describes the no alloy system, its 1 rich organization is 2 mail + but unfortunately can not distinguish their phase interface.

Zr is completely dissolved in the Al phase. The Zl.Aj particles in the alloy system do not play a role in the refinement of the dendrite;21 the addition of yttrium increases, except that part of the solution dissolves in 1 phase except for the presence of force from the particles and acts as a nucleation base for the lychee. Refined. With the increase of 21 additions. There are more and more pre-core 13 particles in the melt. Finally, the long columnar product is transformed into a fine equiaxed product.

3.2 Effect on the size of eutectic silicon morphology As a modifier added to the alloy to make the co-silicon morphology from coarse to 4 grain refiner, it seems that the literature 3 studies the 151 ugly primary silicon reappearance Silicon size, plus and gradually changed from fibrous to pin-like, pay 1 to change the quality of poisoning. weakened. The metamorphic effect. The team knows that other people's research has also found similar phenomena. The effect of some or all of the powerlessness of the goods is considered to be at 5 and the formation of stable boride also. The authors used 1. master alloy as a refinement and added it to a modification of the 71 3 alloy. No similar phenomenon was observed. The eutectic silicon was still fine and fibrous. 4. It is reasonable to assume that it did not weaken the known metamorphic effect.

4 Conclusions: The seven metamorphic 1.61 alloys have the effect of refinement of the anvil. When the addition amount of 1. is 0.6, the dendrite is completely equiaxed.

Deterioration. 1.6 The size of the alloy's broken-phase morphology, especially said that there is no immortal weak 4 metamorphic effect.

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