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Fatigue Testing

Fatigue is a progressive, localized, permanent structural change in a material subjected to fluctuating stresses and strains that may lead to cracking or fracture after a sufficient number of fluctuations. The process of fatigue consists of three stages: first, initial fatigue damage that will lead to crack nucleation and crack initiation; subsequently, progressive cyclic growth of cracks (crack extension) until the remaining uncracked cross-section of the part becomes too weak to sustain the loads imposed; and finally, abrupt fracture of the remaining cross-section. Fatigue of materials can lead to catastrophic failures with little warning. Therefore, it is necessary to perform fatigue testing on the materials.

Alloy fatigue testing can be used to determine the durability and endurance of alloy materials under cyclic loading. This is essential for selecting the right material for a specific application and for predicting the expected life of a component. As a leading provider of alloy fatigue testing services, Alfa Chemistry offers comprehensive and reliable testing solutions to customers worldwide. Whether you are in the aerospace, automotive or medical device industries, Alfa Chemistry's team of experienced scientists and technicians have the expertise and equipment necessary to help you achieve your testing goals.

Our Test Projects

The fatigue test can be divided into high cycle fatigue test and low cycle fatigue test according to the number of failure cycles. Both tests use cyclic loading to evaluate the life of materials that are subject to fluctuating strain and stress conditions that can lead to cracking or fracture. Alfa Chemistry mainly provides these two test projects for customers.

• High Cycle Fatigue Test

High cycle fatigue is the most common form of fatigue testing. It is used to evaluate the behavior of materials under cyclic loading conditions, where the stress amplitude is relatively low and the frequency is high. In general, high cycle fatigue is caused by alternating stresses in the elastic or slightly inelastic range. In the case of high cycle fatigue, material properties are usually characterized by an S-N curve, or stress-cycle curve or fatigue curve.

• Low Cycle Fatigue Test

Low cycle fatigue test generally runs slowly, and the number of cycles to failure is relatively short. The low cycle fatigue mechanism is characterized by a high cyclic stress level exceeding the endurance limit of the material, which is generally considered to be between 10⁴ and 10⁵ cycles. In this case, stress produces both elastic and plastic strains. The latter is particularly important in areas with geometric discontinuities or stress risers. It is worth noting that low cycle fatigue is dominant in features such as cooling holes, internal channels, sharp and discontinuous geometries ^[1].

Our Testing Capabilities

Alfa Chemistry has the capability to perform fatigue testing on the following alloys:

Our Testing Standards

We offer testing for a variety of specifications, including but not limited to the following standards.

We will perform fatigue testing in accordance with the above standards. In addition, we also test according to the customer's specifications and requirements.

Reference

1. Farhat, H. Typical service-induced damages. Operation, Maintenance, and Repair of Land-Based Gas Turbines. 2021: 107-130.