Πολυτεχνική Σχολή
Τμήμα Μηχανολόγων Μηχανικών
Εργασία στο μάθημα Τεχνολογία Υλικών II
ΘΕΜΑ: Effects of testing variables on stress corrosion cracking susceptibility of Al 2024-T351
2η Ομάδα
1. Χαλεβελάκης Ιωάννης ΑΕΜ:1363
2. Πανώρης Κωνσταντίνος ΑΕΜ: 1316
3. Τσιπούρης Γεώργιος ΑΕΜ: 1097
4. Σιώμος Γεώργιος ΑΕΜ: 1077
5. Καθρέφτης Μιχαήλ ΑΕΜ: 1029
Κοζάνη Ιανουάριος 2012
Abstract
In the present study, the effects of testing variables on stress corrosion cracking (SCC) susceptibility of Al 2024-T351 in 3.5% NaCl solution were examined using slow strain rate test (SSRT) method with controlled applied potentials and a constant load test (CLT) method. The SSRTs were conducted at various strain rates and applied potential, while the CLTs were performed with different exposure time, with different grain directions of ST (short-transverse) and L (longitudinal) to understand how the testing parameters affected on the SCC susceptibility of Al 2024-T351. The percent reductions in tensile elongation in an SCC-causing environment over those in air tended to express the SCC susceptibility of Al 2024-T351 most properly for both SSRT and CLT. The present fractographic examination suggested that both anodic dissolution and hydrogen embrittlement played a role in the SCC process of Al 2024-T351 in 3.5% NaCl solution at both anodic and cathodic applied potentials, and the contribution of each mechanism could vary with different testing variables. It was also found that the SCC susceptibility of Al 2024-T351 obtained from the CLT result could provide the similar SCC evaluation result obtained by SSRT with a proper selection of testing variables. The metallurgical aspect of SCC behaviour of Al 2024-T351 was also discussed based on the microstructural and fractographic examinations.
1. Introduction
High-strength 2xxx and 7xxx series aluminium alloys are susceptible to stress corrosion cracking (SCC) which may cause a