Paste for inhibiting fatigue crack growth

Abstract

This paste for inhibiting fatigue crack growth is a mixture of particles and a liquid, said particles having a particle size distribution such that: the abundance ratio of particles of 20mum or less in diameter is 100 mass%; that of particles of 10mum or less in diameter is 95 to 100 mass%; that of particles of 2.0mum or less in diameter is 45 to 99 mass%; that of particles of 1.0mum or less in diameter is 20 to 85 mass%; that of particles of 0.5mum or less in diameter is 7 to 50 mass%; and that of particles of 0.1mum or less in diameter is 0 to 5 mass%. The paste can inhibit the fatigue crack growth of a metal member.

Description

technical field [0001] The present invention relates to a paste for suppressing the growth of fatigue cracks, which is used for suppressing the growth of fatigue cracks generated on metal members. Background technique [0002] Fatigue cracks are cracks formed under repeated stress, and repeated stresses are applied to the fatigue cracks generated on the metal member to cause the fatigue crack to grow and lead to the fracture of the metal member. Therefore, techniques to suppress fatigue crack growth are particularly important. Regarding fatigue cracks, foreign substances such as fretting wear oxides (oxides produced by friction of the oxide layer on the crack surface) are generated in the fatigue crack surface, so the fatigue crack growth rate is reduced due to the wedge effect, which is well known. [0003] The mechanism of fatigue crack growth rate reduction based on the wedge effect is as follows: Figure 8 As shown in Fig. 1 , the displacement of the opening of the cra...

AI Technical Summary

Problems solved by technology

[0014] With regard to the paste described in the above-mentioned Patent Document 1, as described later, there is the following problem: Since the particle size distribution of the alumina particles is not taken into consideration, the range of the stress intensity factor (the range of the stress intensity factor: the expression effect If the range of the stress intensity factor is large, the opening displacement of the crack tip will increase, so the growth rate of the fatigue crack will increase), the difference in magnitude is comparable to that of the case where no paste is used. ratio, sometimes the fatigue crack growth suppression effect becomes small and insufficient

Images