Research on Mechanical Alloying of Immiscible Al-20% Pb Alloy

Kunming Metallurgical Research Institute, Kunming 650031, Yunnan, can obtain homogenous, non-segregated miscible compounds. Analyze that mechanical miscibles are non-equilibrium alloys with high storage energy.

1 former M mechanical alloying anal material technology technology to break the traditional method of casting and powder sintering process manufacturing alloys in the gold manufacturing process, the traditional method is limited by the alloy phase, each component can not be arbitrarily chosen. And mechanical alloying. Each group can be arbitrarily selected according to the needs, and the components can be arbitrarily adjusted. Mechanical alloying technology can produce amorphous quasi-crystal nano-products, which can extend the saturated solid degree. Metastable phases and intermetallic compounds can be prepared in the solid state, and solid state reduction refining can be achieved. In addition, mechanical alloying can achieve atomic-scale mixing, so that a homogenous mixture of structures without segregation can be obtained for immiscible components. This is very effective for the combination of metal elements having different melting points and vapor pressures which are difficult to use in liquid quenching and gas solidification.

For more than a decade, this new technology of mechanical alloying potentiality has shown its attractive charm in the development of new materials, the development of the top 7 and potential, the immiscible alloys in the elemental possession A considerable proportion, such as the date of receipt of 1 peach 6 revised date 1990129 author Ji Hanrong 1939. Yan people. Senior engineer.

Office and so on. Because of the special properties of these non-miscible alloys, it has received much attention. However, such alloys differ greatly in specific gravity or melting point. Melt state 1 or state + miscible, resulting in serious dislocation of the alloy structure. Restricted extensive application of the preparation method of immiscible non-segregation alloy, including micro gravity casting 1 super rheological casting 4 powder metallurgy 5 and rapid solidification 6 These methods are based on the economic difficulty and effectiveness of their implementation of technical difficulty. They are still based on rapid solidification technology and are generally recognized. However, from the standpoint of composition and structure control, it still appears to be insufficient, and it is difficult to fully realize the performance of the alloy.

2 Test procedure and method The mechanical alloying device used in the test is a self-designed high-energy ball mill. Several speed control features such as water-cooled airtight and atmosphere protection. The cylinder volume 8 stirring shaft and arm are stainless steel grinding balls for high chromium steel.

In the corresponding ball than the ball diameter and speed, mechanical alloying speed 500 ball than the class = 10 ball diameter 6 è„Ž under the test.

Scanning electron microscopy 61 was used to observe the composition and distribution of the alloy powder particles. The X-ray diffractometer was used to determine the variation of the unit cell parameters and the degree of powder grain refinement. The difference was determined by differential scanning calorimetry. The melting point of the powder was extremely refined and strongly affected. Strain powder energy storage.

The mechanized metallurgy process and the extraction of defective products are performed in the gas protection and popular glove box. The test object is a friction-reducing layer in a commonly used bimetal bearing. Its composition is 1203 knots, and the phase transition of the alloy in the Sunyuan alloy is balanced with a typical partial crystal structure. 7. The characteristics of this structure are shown in 1. . Even in the 1 alloy powder coating obtained by rapid solidification, the higher melting point component is still the core, the outer layer is 3 shells, and the western net structure is 8. Unless the low pressure is atomized in the air with a particularly high cooling rate. Only in order to obtain a uniform distribution without shell. However, with an increase in the pressure content of 20, the segregated shell structure still appears even when atomized in 101 particles of the powder. This seven segregation structure. From the thermal point of view, it should be a kind of non-equilibrium or metastable state. To achieve this state must apply energy. In the process of mechanical alloying, the components are impacted and slid by the grinding ball medium, resulting in strong plastic deformation, cold welding fracture and fragmentation, resulting in an increase of crystal defects, raising the free energy of the system, and being in a new non-equilibrium state. Metastable.

The morphology of the shell 3.1 and the distribution of the components are at 51 points. , 20., Organizational form and 纟 1. Childhood distribution is obviously not as-cast and rapid solidification in the team over, medium, between the deformation of the component folding and cold welding to form a layered and whirlpool-like composite structure, making due to the proportion The difference in the occurrence of segregation is reduced. As the process progresses, the layered structure becomes finer and smaller, segregation progress decreases, and a uniform distribution without segregation is formed. The typical structure and non-segregation fine particle aggregates formed after processing at 12 and 40 are formed in the Ge 34.

Al particle distribution measurement 5 indicates that the aggregate of spherical fine particles has an average particle diameter of 90 or more. To confirm this distribution of aggregates of different shapes. The results of multi-point measurements from different morphologies were selected to show that the distribution is the same in different aggregates. How different forms of aggregates are formed and how they affect composite structures remains to be studied.

Distribution of particle aggregation morphology The distribution of electrons like 2.21 for a long period of time the structure and characteristics of the formation of the rules and characteristics of the time is about 50, 7. Grain size refinement seems no longer possible. This can be explained by the driving force of retraining by the intense strain system.

Progressive inspections, structures, found through a material hot prayer.

The melting point of the matrix component 1 decreases, and the endothermic peak of the drag disappears. It is possible to form an extended solid solution. For this purpose, the unit cell parameters of the matrix component 1 were determined. As a result, with the advancing of the river, the unit cell parameters tend to increase, but the change is small enough to explain the formation of an extended solid solution. 2 and 8.

The unit cell parameters of the 120 machine change with his elbow time h cell parameter temperature T. Degradation of the cell parameter can be considered to cause grain refinement and strong distortion of the elbow. Introduce a large number of product defects caused by the kind of mechanical miscible body. From. 12 time curve of 120.1, out of 9. After the 1801. system was still a mixture of hunger elements, no new phases and solid solutions were detected.

The energy changes in the system of the Shan 2.3 system were processed by the person 120 who made the mechanical miscible body, and its thermodynamic state changed. This ancestral process energy transmission and transfer tends to be stable. Conversely, changes in state, accompanied by an increase in the free energy of the system, will be in a non-steady state or meta-stable state. In general, with non-equilibrium, such as 2 metastable stabilization, there are cold elements in the transfer of goods, and the speed of products and transitions must be changed, and the type and speed of the conversion products are the activation of the metastable phase stabilization. The heat-activated energy that can be supplied to the outside world is a strong plastic deformation plant that infiltrates the inmates. Increased lattice distortion and product boundary energy. The system can be elevated and is in a thermodynamically stable state. The use of differential testing hot 05, method. The heat cycle of the second thermal cycle heat flow curve for the second generation of the heat cycle of the strong deformation of the system, the second heat cycle non-defective system of energy changes, fitting the system energy temperature relationship, and the selected temperature range 1 grape枳分,1! It is called to find the area of ​​the two curves and save the energy. In one pair of 120 people, one is only 50 in the specified parameters, 50 in the range of 50450, and the storage energy is 3.81 less. At the same time, it can be seen that in the second thermal cycle, the energy of the time nEn enters the energy state system, Some of them are used to form new phases or initiate other phase change learning energies. The other part, in non-chemical energy equilibrium state, must undergo stable transformation. The rate of transformation determines its stability. For the experimental system, good stability still appeared after 4 weeks at room temperature. Stabilizing the rate of change at different temperatures requires further research.

4 Conclusions Mechanical alloying forms an unbalanced structure for immiscible alloys, such as expanding the solid solution nanocrystalline amorphous state, which is an effective means. For the person 1 Yuanyuan series, experiments have shown that no extended solid solution or other metastable phases can be formed, and only mechanical alloy miscible bodies in which the elements are fully refined and uniformly distributed can be obtained. Eliminate component segregation due to the difference in melting point and specific gravity.

20>. Mechanized golding 501. The storage energy of the system is 3.81. It is in a non-equilibrium state. And there is considerable stability at room temperature, and its stabilization temperature conversion rate needs further study.

Pair 1 lanthanide alloy. Machine, alloying technology. Compared with rheological casting, rapid in-greasing and conventional powder metallurgy, the composition segregation is more effectively solved.

9 Bridge according to men. Powder on powder metallurgy, 1995 Yunnan Metallurgy