Phosphorus is a ubiquitous element in our lives, an important component of life and a key ingredient in many industrial products. Today, we will explore the role of phosphorus in superalloys and how the properties of superalloys can be optimized by precisely controlling phosphorus content.
Phosphorus is the 15th chemical element in the periodic table, located in the third period, group VA. Phosphorus is widely distributed in the biosphere, and its content ranks among the top ten in the earth’s crust. Phosphorus is widely found in animal and plant tissues and is one of the most abundant elements in the human body, accounting for about 1% of human body weight. The adult body contains about 600-900 grams of phosphorus, of which 85.7% is concentrated in bones and teeth. The remaining phosphorus is distributed throughout the body in various tissues and fluids, with half of it found in muscle tissue. Phosphorus not only constitutes the composition of the human body, but also participates in very important metabolic processes in life activities. As an important component of DNA and RNA in human cells, phosphorus is very important to the body.
In superalloys, phosphorus has both beneficial and detrimental effects. These different effects depend on the phosphorus content and the type of alloy. Below, we will describe each of these two functions of phosphorus.
Beneficial effects of phosphorus:
Appropriate amounts of phosphorus in superalloys can improve the creep resistance and durability of the alloy. Phosphorus segregates to the grain boundaries of the alloy, and this segregation increases the bonding force between grain boundaries, thereby improving the creep resistance and durability of the alloy.
However, the higher the phosphorus content in the alloy, the better. On the one hand, phosphorus is harmful to alloys. On the other hand, as the phosphorus content increases, the creep resistance of the alloy first increases and then decreases. Research shows that the creep resistance of the alloy reaches its maximum when the phosphorus content reaches 0.005% to 0.016%. The graph below shows the creep properties of the alloy as a function of phosphorus content.
In the study of Inconel 718, the researchers smelted four compositions containing 0.0008%, 0.01%, 0.016% and 0.04% phosphorus. The final results showed that a phosphorus content of 0.016% gave the alloy the best creep resistance.
Harmful effects of phosphorus:
Phosphorus in superalloys can cause segregation of alloying elements during solidification. This segregation leads to the precipitation of Laves phase in the alloy. The Laves phase is a harmful phase that acts in alloys as a channel for crack formation and propagation. At the same time, it consumes the niobium element in the alloy, which reduces the amount of strengthening phases and significantly reduces the tensile properties of the alloy during the aging treatment.
For cast superalloys, the alloy is formed by solidification. Therefore, it retains the negative effects of phosphorus to the greatest extent possible. This negative effect can be partially eliminated by heat treatment or heat treatment of wrought superalloys. Therefore, it suffers relatively limited harmful effects from its phosphorus content.
After testing, when the phosphorus content is less than 0.008%, it has little impact on the performance of the alloy. Once the phosphorus content exceeds this amount, the properties of the alloy will be significantly reduced.
in conclusion:
Phosphorus plays two roles in superalloys. It can improve the creep resistance and durability of alloys by increasing the bonding strength of the crystals. It will also make the alloy more likely to precipitate harmful phases and reduce the tensile properties of the alloy. In actual projects, we should choose the appropriate phosphorus content according to different alloys to maximize the performance of the alloy.
Tianjin Anton Metal Manufacture Co., Ltd. is a company specializing in the production of various nickel-based alloys, Hastelloy alloys and high-temperature alloy materials. The company was established in 1989 with a registered capital of 10.0 million, specializing in the production and sales of alloy materials. Anton Metal’s products are widely used in aerospace, chemical industry, electric power, automobile, nuclear energy and other fields, and can also provide customized alloy material solutions according to customer needs. If you need to know the price consultation of alloy materials or provide customized alloy material solutions, please feel free to contact the sales staff.
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Post time: Dec-25-2023
