Method for measuring critical temperature of high temperature creep crack growth of material

Abstract

The invention discloses a method for measuring critical temperature of high temperature creep crack growth of a material. The method comprises the following steps of: processing not less than 6 standard compact tension specimens through a specific material according to creep crack growth test requirements, performing crack prefabrication on the processed not less than 6 test specimens on a fatigue performance tester, wherein the prefabricated crack length is 0.5 times as large as the width of the test specimen; wedging a wedge-shaped block in an initial slot of the test specimen, locating the most front end of the flat part of the wedge-shaped block at a loading line to provide displacement to the loading line, and forming a stress strain field characterized by stress strength factors at the crack tip of the test specimen to provide a driving force for creep crack growth; and putting the assembled test specimen in a resistance wire heating type high temperature furnace to perform heating test or cooling test until the crack growth speeds of all test specimens at a temperature are not larger than 1*10<-6>m / h, and the temperature is the critical temperature of high temperature creep crack growth of the material. The method disclosed by the invention can be used for testing a plurality of test specimens at one time, so that the test cost is greatly lowered.

Description

technical field [0001] The invention relates to a method for measuring a creep mechanical property parameter of a material, specifically a test method for determining a creep crack growth critical temperature by using a high-temperature prestressed creep crack growth test. technical background [0002] Creep refers to the slow plastic deformation of materials under stresses above and below the material's macroscopic yield limit. In the stress range where grain boundary damage occurs, wedge-shaped cracks form at higher stresses leading to local grain boundary separation, and the cracks interact and connect leading to eventual fracture; at lower stresses, creep damage manifests as nucleation of grain boundary voids , grow and merge, and then break. [0003] Creep crack growth is the macro manifestation of creep damage, and the growth process of macro cracks accounts for a large part of the creep rupture life. Creep crack growth is a very complex mechanical behavior, and the ...

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Problems solved by technology

[0006] It can be seen from this that the approximate value method used in engineering is not supported by experiments and theory; the method in literature [3] needs to be equipped with a high-temperature furnace on the load testing machine, and then equipped with equipment to measure the crack length. The test equipment has high requirements, and only one test piece can be tested at a time

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