What are the difficulties in high-temperature alloy processing technology?

As a key material that can maintain stable performance in extreme high temperature environments, the processing technology of high-temperature alloys has always been a major challenge faced by the manufacturing industry. Due to their complex composition and unique properties, this type of material presents unique technical difficulties in every step from cutting to forming to subsequent processing, which places extremely high demands on processing equipment and craftsmanship. ​

In the cutting process, at room temperature, the hardness of many high-temperature alloys is significantly higher than that of ordinary steel. However, during the cutting process, as the temperature increases, their strength not only does not decrease, but may also remain or even increase, forming the phenomenon of “high-temperature strengthening”. This causes the cutting tool to withstand tremendous cutting force during cutting, and the blade is prone to cracking or wear. At the same time, high-temperature alloys have extremely poor thermal conductivity, making it difficult for the heat generated during cutting to dissipate quickly. A large amount of heat accumulates in the contact area between the tool and the workpiece, leading to a sharp increase in tool temperature, accelerated tool wear, and even problems such as tool adhesion and curling, seriously affecting machining efficiency and surface quality. ​

Forming processing also faces many challenges. The plasticity of high-temperature alloys is poor, especially at room temperature, where the plasticity is significantly insufficient. When forging, rolling, and other plastic forming processes are carried out, larger external forces need to be applied. Moreover, it has high deformation resistance and is prone to uneven deformation during the forming process, resulting in cracks or internal defects in the workpiece. For some complex shaped components, such as aircraft engine turbine blades, precision forming is required, but their poor flowability makes it difficult for the material to fill the mold cavity, making it difficult to ensure the dimensional accuracy and shape integrity of the formed parts. In addition, high-temperature alloys have a high elastic modulus and severe rebound phenomenon after forming, further increasing the difficulty of obtaining accurate dimensions. ​

The control of heat treatment processes is also highly challenging. High temperature alloys contain various alloying elements, such as chromium, nickel, tungsten, molybdenum, etc. These elements have different diffusion rates during heat treatment, which can easily form compositional segregation and affect the uniformity of material properties. Moreover, different types of high-temperature alloys require specific heat treatment processes, such as solution treatment, aging treatment, etc. Small changes in temperature, time, and other parameters can lead to changes in the precipitation quantity and morphology of strengthening phases, thereby affecting key properties such as strength and toughness of the material. At the same time, oxidation, decarburization and other problems may occur during the heat treatment process, which can damage the surface quality of the material and require additional treatment processes to compensate. ​

The difficulties of high-temperature alloy processing technology run through the entire processing flow, from tool wear and heat accumulation during cutting, to insufficient plasticity and rebound problems during forming, to composition segregation and performance fluctuations during heat treatment. Each link requires precise process control and advanced technical support. With the continuous expansion of the application field of high-temperature alloys, research and optimization of their processing technology will also continue to be promoted.