Irradiation effect on impact fracture behavior of A508-3 steel in ductile-to-brittle transition range

Abstract

The mechanical performance of reactor pressure vessel (RPV) materials is an important factor in determining the safety and economics of the operation of a nuclear power plant. The ductile-tobrittle transition temperature (DBTT) tested by Charpy impact test is an important parameter for evaluating the RPV embrittlement. In this paper, the Charpy impact test of RPV steel prior and after irradiation was carried out at different temperatures. The fracture morphology was observed by scanning electron microscopy. The irradiation effect on the impact fracture behavior was analyzed in the DBTT temperature zone. Results show that in the DBTT range, the crack initiation and propagation energy are obviously reduced for the irradiated material. After irradiation, the dimple area on the fracture surface is significantly reduced, and the distance from the crack initiation source to the gap is decreased. For the RPV steel with low Cu steel content, matrix damage becomes the main factor on material irradiation embrittlement.

Comparison of mathematical and supervised machine-learning models for ductile-to-brittle transition in bcc alloys

“…The fraction of brittle region on fracture surface, f B , is defined as f B = 1 − f D . Thus, the rate of change in impact energy with temperature, given by equation (6), is proportional to the product of fractions of brittle and ductile regions.…”

“…The DBT behaviour is influenced by several factors, e.g. nature of alloying elements [2], secondary phases in matrix [3], radiation damage in Reactor Pressure Vessel (RPV) steels [4][5][6][7][8], microstructure [9], residual strain [10], grain boundary characteristics [11].…”

Non-hardening embrittlement mechanism of pressure vessel steel Ni-Cr-Mo-V welds during thermal aging

“…The future work will be developing a framework of lifetime prediction considering thermal aging mechanism for engineering structures. [23][24][25][26][27][28][29] Some new designs of the structures inspired from composite materials made with the additive manufacturing technique may be helpful for future RPV material. 30,31…”

A New Fracture Analysis Technique for Charpy Impact Test Using Image Processing

“…The Charpy impact test, one of the fracture behavior tests, is a method for measuring material properties such as the ductility or toughness of materials. The method measures the amount of energy that the materials absorb before fracture, and is used not only to indicate the toughness of the material but also to identify ductile-brittleness changes according to temperature [1][2]. The percentage of shear area is calculated based on the fracture area which is judged directly by the analyzer with the naked eye.…”