Effect of Aging Process on the Distribution of Two Cobalt-based Superalloys and Alloying Elements

1 test material. Therefore, it is required that the material should have high high temperature and long-lasting strength, tissue stability, and thermal corrosion resistance.

During the second material test, the cast cobalt-base superalloy was mainly strengthened by the carbide phase, and the solid solution strengthening was supplemented. 2. The long-term service under the working conditions of the alloy was similar to the long-term aging treatment. Therefore, the Mu experiment was conducted in the area where the 67088 carbides were prone to change and the 1250 simulation temperature was used. The timeliness of several processes was targeted to study the effect on the structure and structure of the materials. The materials were processed into small specimens and placed in separate specimens. The selected temperature of the furnace heating, and then select the insulation time for aging. After the aging 3 test results and analysis 31 Microstructure 31 The as-cast microstructure of the cobalt-based alloy microstructure of the matrix 7 phase and eutectic carbide white and gray two kinds of composition carbide distribution in the dendrite II Bureau 3.1 .2 After aging, the microstructure of alloy 20 is alloy 67. During ageing, firstly granular carbides are precipitated around the massive carbides and between the dendrites, and granular and acicular carbides are observed over time.

When 0150 alloy was aged at 670 and 71, carbides precipitated slightly. At 880 and 1 ageing, granular carbides were precipitated between the massive carbides 1 and 1250241.1 were aged. Slightly small granular carbides were formed. 3.

The variation of Vickers hardness values ​​of the as-cast and aged specimens is plotted as a curve of hardness and time. 7 The peak values ​​of the hardness values ​​at different temperatures and ages show a peak, and the osmotic hardening is at a high temperature of 1250. , 2, the serious oxidation, the oxide layer and the substrate is weak, and in the local oxidation pit uneven oxidation, the 50 oxide layer is dense, and the substrate with strong, uniform oxidation.

4 Discussion of the as-cast drill base; 1 temperature alloy with 10., and milk 3 carbide phase enhancement is small. Strong carbides are formed to form elemental formations, rivers 7, and 3, and therefore, 0.10 30 carbon is often present in the alloy. In the No. 50 alloy, carbon content is small, but it also contains strong carbides to form Alizarin. Therefore, it is mainly MC reinforced. MC melting point is very high, high temperature stability, llj effect pay Jl shape effect is very small, so Jia 50 alloy structure is stable. In the 20 alloys, the precipitation is mainly composed of PCT and Cu, and the complex carbides are distributed between the dendrites and the grain boundaries. After the aging, the carbides are precipitated between the dendrites and the bulk carbides. As time goes by, the morphology of aggregated granular carbide 1 does not change during aging.

In the aging process, the granular heart 3 precipitates and age hardens. This is because the casting cooling process is not a slow cooling process. Organizations cannot balance changes and are unstable. During aging, due to the increase in the diffusion capacity of alloying elements, the alloy elements that were too late to precipitate are desolventized in a stable phase. Due to the presence of a large amount of chromium and carbon in the cobalt alloy, dissolution-based high-chromium carbide shoulder aging time Prolonged, aggregated growth and reduction of chromium, nickel and carbon content in the matrix, the effect of aging strengthening and solid solution strengthening weakened, and the Vickers hardness peaked. 0 Jia 20 alloy at 88,1 or more temperature aging, 123, aggregate growth and began to reverse transformation, the emergence of needle-like PCT 4.

Due to the high temperature at 1250, the alloy 0 is more severe than the alloy 0, and the oxide layer is weakly and non-uniformly oxidized with the matrix. Therefore, it is illustrated that the 50 alloy has a history of more than 10,20 alloys suitable for service at high temperatures.

Cobalt has a stable face-centered structure at high temperatures. At temperatures below 400, dense hexagonal structures are present. , 7.20 and, the boundary 50 alloy contains a large amount of iron and nickel, the weight percentage of up to 2 off, inhibiting the conversion of cobalt to close-packed six-party at low temperatures. From Court 4, it can be proved that the base break is face-centered cubic structure at high temperature.

5 Conclusion 0 00 alloy than 0120 alloy high-temperature aging stability of the organization of high anti-oxidation ability and resistance to creep, more suitable for high temperature service in 100, above.

Mainly, supplemented by solid solution strengthening, River 7, unstable in the middle temperature aging, decomposed in the 67088 buckle, but in 100, aging and 880, long-term aging, there will be a reverse change.

III US 01. Sims waits, Zhao Jie et al. High-temperature alloys Aerospace and high-temperature materials for industrial power Dalian Dalian University of Technology Press, 1992186104.2 Yao Xiangdong Zhang Jinghua waiting. Chinese Journal of Metals, 1995.12,534 3 pay side. Raschko et al. Physical and chemical phase analysis of steel and alloys 1982; 228 2344 Shanghai Jiaotong University metallographic analysis writing group. Metallographic analysis. Shanghai 1964,479