Powder Metallurgy High Temperature Alloys
These alloys first originated as dispersion-reinforced alloys, and in 1962, based on the principle that thorium dioxide has a dispersion-reinforcing effect in tungsten, DuPont developed a high-temperature material made of thorium dioxide dispersion-reinforced by powder metallurgy process, called TD nickel, which started the production of powder metallurgy high-temperature alloys.
Powder metallurgy high-temperature alloys are usually divided into two categories: dispersion-reinforced and precipitation-reinforced, according to the way the alloy is strengthened. Dispersion-reinforced high-temperature alloys are strengthened with inert oxides, which are highly stable in their physical and chemical properties and maintain a fairly high strengthening effect at temperatures where the general precipitation-reinforced phase softens, aggregates or even dissolves. Because this inert oxide must be diffusely and uniformly distributed to have the strengthening effect, and it is very different from the specific gravity of the base alloy, it can not be produced by conventional melting process, but only by powder metallurgy methods. In addition to the dispersion-reinforced high-temperature alloys made by internal oxidation, chemical co-precipitation, selective reduction and other methods, J.S. Benjamin of the United States in 1970 and for the first time with a new process of mechanical alloying made of yttrium oxide dispersion-reinforced high-temperature alloys. Mechanical alloying is the use of metal powder or intermediate alloy powder mixed with oxide dispersion phase, ball milling in a high-energy ball mill, so that the powder repeatedly welded, broken, so that each powder into a "micro alloy" particles. This new process allows the manufacture of dispersion-reinforced high-temperature alloys with very complex compositions.
High-temperature alloys made by powder metallurgy process. The development of modern jet propulsion technology, the working temperature and performance requirements of high-temperature alloys are increasing. The preparation of high-alloyed high-temperature alloys by deformation process and casting process can no longer meet the requirements due to the serious segregation of ingots, poor processing performance and forming difficulties. The use of powder metallurgy process, due to the fine powder particles, fast solidification speed, alloy composition is uniform, so the product does not have macroscopic segregation, stable performance, good processing performance, and can further improve the degree of alloying. In the powder metallurgy technology using hot isostatic pressing direct forming or forging with superplasticity isothermal forging into close to the size of the product process, but also to improve metal utilization, reduce the amount of machining, thereby reducing costs. The disadvantage of powder metallurgy technology is that the metal powder is easy to oxidation and pollution, process requirements are strict. According to the alloy strengthening method can be divided into precipitation strengthening type and oxide dispersion strengthening type two categories (see metal strengthening).
Precipitation-reinforced powder high-temperature alloy In the early 1960s, the United States began to use ordinary powder metallurgy process to make high-temperature alloy, failed. late 1960s, the use of inert gas (or vacuum) atomization of pre-alloy powder, and the use of hot isostatic pressing, hot extrusion and superplasticity isothermal forging and other modern powder metallurgy process, made of high-temperature alloy. Britain, the United States and other countries developed into several powder high-temperature alloys, has been used to manufacture high thrust-to-weight ratio (thrust / weight) engine high-pressure compressor disc and turbine disc. The United States with rapid solidification of the new alloy made of powder process has been processed into air-cooled turbine blades, is on trial. Turbine discs made from high-temperature alloy powder.
Powder metallurgy high temperature alloy
Figure 3 Powder Metallurgy High Temperature Alloy
Figure 3 Powder metallurgy high temperature alloy
① The production of solid solution strengthening type dispersion strengthening alloy, generally using the chemical co-precipitation method, that is, first of all, the metal oxide into a water sol and with the matrix of each group of metal salts and precipitating agent mixed aqueous solution of the three in a specific container, so that the generation of the oxide plasmas as the core of the composite precipitates, after various heat treatment to make materials.
② The production of precipitation-reinforced dispersion-reinforced alloys uses a mechanical alloying process in which metal powder, intermediate alloy powder and oxide powder are placed in a stirred ball mill, and the raw material powder is crushed, mixed and cold-welded together under vacuum or protective atmosphere to achieve alloying, and its alloying process. The alloys produced by this method are MA754, MA956, MA6000, ODS-WAZ-D, etc. Its process flow
Powder metallurgy high-temperature alloys are usually divided into two categories: dispersion-reinforced and precipitation-reinforced, according to the way the alloy is strengthened. Dispersion-reinforced high-temperature alloys are strengthened with inert oxides, which are highly stable in their physical and chemical properties and maintain a fairly high strengthening effect at temperatures where the general precipitation-reinforced phase softens, aggregates or even dissolves. Because this inert oxide must be diffusely and uniformly distributed to have the strengthening effect, and it is very different from the specific gravity of the base alloy, it can not be produced by conventional melting process, but only by powder metallurgy methods. In addition to the dispersion-reinforced high-temperature alloys made by internal oxidation, chemical co-precipitation, selective reduction and other methods, J.S. Benjamin of the United States in 1970 and for the first time with a new process of mechanical alloying made of yttrium oxide dispersion-reinforced high-temperature alloys. Mechanical alloying is the use of metal powder or intermediate alloy powder mixed with oxide dispersion phase, ball milling in a high-energy ball mill, so that the powder repeatedly welded, broken, so that each powder into a "micro alloy" particles. This new process allows the manufacture of dispersion-reinforced high-temperature alloys with very complex compositions.
High-temperature alloys made by powder metallurgy process. The development of modern jet propulsion technology, the working temperature and performance requirements of high-temperature alloys are increasing. The preparation of high-alloyed high-temperature alloys by deformation process and casting process can no longer meet the requirements due to the serious segregation of ingots, poor processing performance and forming difficulties. The use of powder metallurgy process, due to the fine powder particles, fast solidification speed, alloy composition is uniform, so the product does not have macroscopic segregation, stable performance, good processing performance, and can further improve the degree of alloying. In the powder metallurgy technology using hot isostatic pressing direct forming or forging with superplasticity isothermal forging into close to the size of the product process, but also to improve metal utilization, reduce the amount of machining, thereby reducing costs. The disadvantage of powder metallurgy technology is that the metal powder is easy to oxidation and pollution, process requirements are strict. According to the alloy strengthening method can be divided into precipitation strengthening type and oxide dispersion strengthening type two categories (see metal strengthening).
Precipitation-reinforced powder high-temperature alloy In the early 1960s, the United States began to use ordinary powder metallurgy process to make high-temperature alloy, failed. late 1960s, the use of inert gas (or vacuum) atomization of pre-alloy powder, and the use of hot isostatic pressing, hot extrusion and superplasticity isothermal forging and other modern powder metallurgy process, made of high-temperature alloy. Britain, the United States and other countries developed into several powder high-temperature alloys, has been used to manufacture high thrust-to-weight ratio (thrust / weight) engine high-pressure compressor disc and turbine disc. The United States with rapid solidification of the new alloy made of powder process has been processed into air-cooled turbine blades, is on trial. Turbine discs made from high-temperature alloy powder.
Powder metallurgy high temperature alloy
Figure 3 Powder Metallurgy High Temperature Alloy
Figure 3 Powder metallurgy high temperature alloy
① The production of solid solution strengthening type dispersion strengthening alloy, generally using the chemical co-precipitation method, that is, first of all, the metal oxide into a water sol and with the matrix of each group of metal salts and precipitating agent mixed aqueous solution of the three in a specific container, so that the generation of the oxide plasmas as the core of the composite precipitates, after various heat treatment to make materials.
② The production of precipitation-reinforced dispersion-reinforced alloys uses a mechanical alloying process in which metal powder, intermediate alloy powder and oxide powder are placed in a stirred ball mill, and the raw material powder is crushed, mixed and cold-welded together under vacuum or protective atmosphere to achieve alloying, and its alloying process. The alloys produced by this method are MA754, MA956, MA6000, ODS-WAZ-D, etc. Its process flow
Nickel-based alloy applications
Cobalt-based alloys
Cobalt-based high-temperature alloys
Solid solution reinforced alloys
Casting alloys
Single crystal alloy
Nickel-based single crystal alloy
Directional crystalline high temperature alloys
Deformed high temperature alloys