Zliatina teplo úprava technológia vývoj

Nickel-based casting high-temperature alloy heat treatment, refers to the nickel-based high-temperature alloy products in the as-cast state, the use of heating, insulation and quenching of the processing method, in order to achieve the expected microstructure and mechanical properties of a class of metal materials thermal processing technology. It is of positive significance to study the effect of heat treatment on the microstructure of alloys in order to explore the mechanism of good heat treatment to improve the high-temperature properties of alloys. Among them, solid solution treatment and aging treatment are the main heat treatment processes. Solid solution treatment refers to the heat treatment process in which the excess phase in the microstructure of the alloy is fully dissolved into the matrix phase and then rapidly cooled to obtain a supersaturated solid solution. Solid solution treatment can strengthen the solid solution and improve the corrosion resistance of the matrix, at the same time can eliminate residual stresses in the matrix casting, generally as a preparatory heat treatment, for subsequent machining and subsequent aging treatment to prepare. Ageing treatment refers to the temperature interval in the precipitation of reinforcing phase heating and maintained for a period of time, so that the reinforcing phase of high-temperature alloys precipitated uniformly, thereby improving the strength of castings. In recent years, domestic researchers have also carried out more extensive and in-depth studies on the heat treatment process of nickel-based casting alloys. Yang Heyang on the new nickel-based single-structure high-temperature composites containing rare earth metals, explored the influence of different heat treatment methods on its structure and properties, using differential thermal analysis to determine the solid-phase line of the composite material and the liquid-phase line of the temperature, using metallurgical test method to determine the initial melting temperature of the composite material, and finally formulated the composite material's heat treatment technology methods. Matt et al. thoroughly studied the influence of various heat treatment methods on the mechanical properties and structure of GH4169 alloy, and the results showed that, when the temperature of solid solution treatment is very low, the metal ′ phase will be fully melted and produce the structure coexisting with the unevenly shaped ′ phase, which can inhibit the growth of the metal grain, thus increasing the plasticity and hardness of the alloy, and the plasticity and hardness of the alloy can be increased in the case of prolonged ambient temperature is lower and the aging time is longer. The number of ′ can be increased in the case of longer ambient temperatures and longer aging times, so that the hardness of the alloy increases but the plasticity decreases. Wang Shusen et al. carried out mechanical property tests on isothermally cast GH4169G alloys after different hot working and creep, and the results showed that the δ phase in the alloys generally showed a particle or needle-like shape after hot working by direct aging and primary solid solution, secondary aging methods. Direct aging reduces the stress concentration of the alloy and retards the formation and enlargement of cracks, while standard heat treatment greatly reduces the bond hardness of the austenite grain boundaries, thus promoting the formation and enlargement of cracks in the austenite grain boundaries. Inconel718 nickel-based alloy was taken as the main research object by Dou Xuezheng et al. The interrelationships between microcomposition, thermomechanical properties and corrosion resistance of the alloy under various heat treatments and processing regimes were studied in depth, and the results showed that along with the increase of solid solution temperature, the δ-phase of the alloy was further dissolved, and the δ-phase was sufficiently melted when the solid solution temperature was increased from room temperature to 1020 degree . In addition, the oxidation resistance of the solid solution treated Inconel 718 alloy is slightly better than that of the solid solution + aging treated alloy material [4]. Zhu Yong et al. took the production of a nickel-based alloy for the exhaust valve of an internal combustion engine as the main scientific research objective, and explored the role of the indoor temperature dynamics of the alloy at three different thermal processing regimes (T1: 850 degree × 4 h, AC.+730 degree × 4 h, AC.; T2: 704 degree × 24 h, AC.; T3: 760 degree × 16 h, AC.). The experimental results show that: the alloy under the T1 regime is the strongest and toughest, up to 347 HV10; the tensile strength ratios of the alloy at room temperature under the T1 and T3 regimes exceed 1 200 MPa; the ductility ratio under the T2 regime is the best, more than one-third of the total, which is particularly suitable for working environments with high requirements for plasticity [5]. After exploring the effect of solid solution strengthening treatment time on the distribution of Re and Ru elements and their micro-morphology in nickel-based high-iron alloys, Feng Yueh-enthalpy et al. concluded that, due to the obvious effect of solid solution strengthening treatment time on the distribution of Re and Ru elements, when the solid solution strengthening time is less than 1 h, the Re and Ru components are obviously segregated; when the solid solution strengthening time reaches 20 h, the segregation of both elements is obviously improved. Guiyuan et al. studied the effect of solid solution treatment on the microcosmic composition and the degree of segregation of a nickel-based single-crystal casting high-temperature alloy, and found that the alloy has significant segregation in the as-cast organization, and through the optimization of the heat treatment system to improve the solid solution temperature can effectively reduce the segregation of alloy constituents.