Method for measuring high-temperature fracture toughness JIC of high-toughness alloys

Abstract

The invention discloses a method for measuring high-temperature fracture toughness JIC of high-toughness alloys, and relates to the technical field of fracture mechanics. The method comprises the steps of processing a compact tension specimen and forming a V-shaped slot in the tip position of a gap in the side surface of the specimen; carrying out fatigue crack prefabrication on the specimen; carrying out a tension test after heating and heat preservation so as to obtain a load displacement curve, snapping the specimen after cooling, and measuring the lengths of quasi-static cracks; regularizing the load displacement curve and carrying out parameter fitting to obtain a load displacement fitting curve; and iteratively calculating the lengths of the cracks, fitting the test data to obtain aresistance curve, and solving a JIC value. The method for measuring the high-temperature fracture toughness is disclosed on the basis of a load separation method, the high-temperature load displacement curve of the compact tension specimen is processed through a regularization method, and the length of the quasi-static crack corresponding to each point on the curve is iteratively calculated, so that a J integral value is effectively measured and then the high-temperature fracture toughness is calculated.

Description

technical field [0001] The invention relates to the technical field of fracture mechanics, in particular to a method for measuring the high-temperature fracture toughness J of high-toughness alloys. IC Methods. Background technique [0002] In recent years, people have paid more and more attention to the study of fracture toughness of welded engineering structures. Some major engineering structures, such as nuclear reactors, large ships, offshore platforms, oil and gas pipelines, etc., will face heavy losses and disasters once cracks appear that may lead to structural disintegration. Therefore, the study of fracture toughness of welded engineering structures is important in theoretical research and It is of great significance in engineering applications. The parameters for evaluating the fracture toughness of materials are fracture toughness K IC 、J IC and crack tip opening displacement CTOD, etc. For most metal materials, the K IC However, for structures made of a larg...

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Problems solved by technology

Among them, the multi-sample method has high accuracy, but it needs to consume a large number of samples to obtain a resistance curve, which increases the test cost; moreover, the multi-sample method requires each sample to be heated and kept warm, the test period is long, and the test efficiency is low

Among the commonly used single-sample methods, the unloading flexibility method requires repeated loading and unloading of the sample, and creep phenomenon is easily induced at high temperature and affects the test results.

Potentiometric methods can only be applied at a single temperature due to changes in material conductivity at high temperatures

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