Materials Science and Engineering Preparation of Microstructure of Molybdenum and Copper Alloys by Powder Method He Zhong Institute of Metals and Chemistry, Ministry of Railways. Beijing 100081i has a transition zone with a width of 1 to 20 between the molybdenum grains and the copper phase. The properties of the alloy with this microstructure are also discussed.

With the increase of IC operation speed and the increase of integration scale, the thermal performance of integrated circuit substrates has become an important issue. Elbow, 1 alloy is considered to be one of the few thermal dissipative materials that can meet the needs of integrated circuits. 1 3! The research and development of such alloys in foreign countries continues uninterrupted. In theory, the microstructure of alloys is mainly affected by their thermal properties, and the prediction of relevant properties is based on microscopic analysis to facilitate the preparation of new materials. The literature reports that former Soviet Union scholars have observed through experimental observation that the activation process of the PCT alloy is sintered. 1 There are chain elbow and grain structure in the microstructure of the alloy, but the reason for its formation has not been analyzed. In this paper, the same mechanical activation process is used to produce alloy 1 and its microstructure and its performance are studied.

2 The research method adopts average particle size as follows: 1. Purity of molybdenum powder with a purity of 99. 娲 and purity greater than 99. 贽 Average particle size of 7, copper powder, at the end of self-made, steel compression molding under appropriate pressure, sample size is 403愀3 The relative density of the compacts is 70. The compacts are placed in a molybdenum furnace with a dry hydrogen gas, sintered at a selected sintering temperature of 1030, and then the relatively high density samples are taken in electronic scanning from the micromirror. Cambridge, UK; 51 and 1 800 TEM observations, testing its density hardness intensity and thermal expansion properties 3 Results and discussion 3. The microstructure of the alloy is bonded phase, the white area is the elbow phase, phase Evenly distributed.

Observing the morphology of the tissue carefully, we can see two kinds of elbows, phase organization, the first is a fine and spherical PCT, phase, and the first one is combined with the strip phase structure. The sample is placed under an electron transmission microscope and clearly visible. Observed 妃, phase condition 胗 胗 胗 胗 胗 胗 胗 胗 胗 胗 胗 胗 胗 胗 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。.

The grain boundaries between crystal grains are divided into a single line, and the single grains with oval shape in the buckle shape have a polygonal shape, and the number of the latter grains is higher than that of the former. , 231. From these observed results, it can be concluded that the small spherical core in the low-intensity microstructure is a single elbow, a grain or multiple, aggregates of grains. Focus on the observation of PCT, crystal grain aggregates can see multiple grain tilts, and small ones are afraid of adding (3). We believe that the elbow-phase stripe in low-intensity tissue morphology is the development of lamellae formed by powder during the mechanical activation process, elbow 0! The mixed powder melts into a liquid phase at a high temperature, and the lamellar elbow 0 particles undergo particle rearrangement through the action of a liquid phase. Dissolved and precipitated, the connection grows at its contact, and partially retains the lamellar morphology. It is connected in series to a bar-like lumpy junction with a grain boundary, which is a chain in the low-order microstructure. The formation of phase structure, such as the dislocation caused by cooling after sintering, and the mechanical activation treatment process, due to processing, 1 particle repeated deformation, with a large number of grains combined with the transition zone between the 3.2 alloy phase In addition to a clear observation under the electron transmission microscope, in addition to the grain condition, there can also be seen a transition zone between the elbow and the phase, progressive enlargement 4, its width is 1020 legs although the high temperature, in, the solubility is very small Because of the mechanical activation treatment used in this experiment, the elbows and particles have higher lattice distortion and larger surface energy. When sintering at high temperature, there will be an imbalance between 1 and thus changing the 0 in the liquid phase 1 Solubility. From the energy spectrum analysis of this area, we know that elbows in the area of ​​5,1 on both sides of the 1 phase boundary have a large area of ​​1 in each other, reaching a 3-pole concentration, but only on both sides of the phase boundary. In the vicinity of each one, that is, when each of the five-pole concentrations is present, a clear transitional layer may occur, possibly a new phase. Exceeding this area, the diffusion between each other cannot change their crystal structure. In other words, the elbows are sintered at high temperature, and in the liquid phase, the dissolution in 1 occurs only in the area of ​​102,1 thick at the particle surface. Exceeding this area, there is a certain diffusion, but the diffusion distance is not large. This also shows that 0 ! In the alloy, only when the liquid phase is generated at the initial stage of sintering, when the individual particles are completely surrounded by the liquid phase, they grow into oval particles. When a crystal grain is connected, the growth of the solid phase contacting the neck is much faster. Yu, the speed of analysis in the live. As a result, the microstructure of the 3.3-bar alloy formed by the seven-phase connection grows to influence its performance. This microstructure of gold changes the properties of the alloy. The density, hardness and strength of the alloy are higher than those of the alloy sintered by the direct mixing method. The transition layer structure, such as 71, has a larger coefficient of thermal expansion than the alloy obtained by melt leaching, and is less than the calculation of the coefficient of thermal expansion obtained by Xian et al. Stretch roll forging and pressing treatment Mechanical activation treatment Mechanical activation without treatment Alloy composition coefficient of thermal expansion The alloys produced in this experiment, 36,1 Calculate the reason for this result by using the formula of 0 in this experiment. The reason can be analyzed from the preparation process of the material and adopt mechanical activation. The process enables the powder to have a higher surface energy, which can be sintered at a slightly lower temperature to achieve a higher density and at the same time make the microstructure of the alloy after sintering small and easy for the mechanical processing of the material due to the transition zone generated between the sintering + Change the solubility of D, in the phase, so that the coefficient of thermal expansion of the alloy 4 changes in this experiment. 4 Conclusions, Transmission electron microscopy analysis of the alloy There is a transition zone with a width of 1 in 201 between the phase grains and the binder phase copper. In this zone, the interdiffusions occur. 2. The microstructure analysis shows that the chain structure of the elbow 1 alloy is due to the elbow, 0, and powder. After the mechanical activation treatment, the difference between the thermal expansion coefficient of the alloy and that of the alloy obtained by the melt leaching method is more severe than that of the rotation of the alloy during the sintering process. Chinese Journal of Semiconductors, 1995289, Continued on page 77 Tsuchiya Man, Tian Dao Cheng Guang. Japanese Open Franchise Publishmen, Te Kaiping 5195006, 1993 Li Xiaohong, Zi Zhangjian Jean Several Journal of Beijing University of Science and Technology, 1996, 185424427 Li Xiaohong, Xie Zizhang, Yang Rang. Several Journal of Beijing University of Science and Technology, 1996, 184330333