Influence of the Upper Die and of the Indenter Material on the Time to Rupture of Small Punch Creep Tests

摘要

The Small Punch Creep test has proven to be a suitable technique for assessing the properties of in-service components. It is a reliable, efficient and cost-effective test for predicting the behaviour of the material. The aim of this paper is to analyse the influence of different factors on the Small Punch Creep (SPC) tests. The influence of the specimen clamping has been studied, experimentally and by means of finite element models on different materials. In the analysed conditions, it has been proven that the influence of the upper die on the tests results is generally relatively insignificant, even in the absence of upper die.Furthermore, the use of different materials at the punch has also been analysed. In order to achieve this goal, SPC tests have been carried out on two light alloys (AZ31 and AlSi9Cu3) at 473 and 523K. Three different balls have been employed: ceramic, tungsten-carbide and steel balls. It has been proven that for the creep ductile alloy (AZ31), there is no apparent effect on the specimen response. On the other hand, for the creep brittle alloy (AlSi9Cu3), a different trend of the material response is shown, dependent on the ball used. As a result, there seems to be a significant influence of the friction between the punch and the specimen on the tests results, related to the material behaviour.