PSI - Issue 23

Barbara Nasiłowska et al. / Procedia Structural Integrity 23 (2019) 583 –588 Nasiłowska B. / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 7. Intrusion of Al-Mg-Fe-Si inter-metallic phase, (a) SE – SEM; (b) EDAX – SEM

An increase in large allocations of inter-metallic phases reduces mechanical properties, especially alloy plasticity. They particularly adversely affect the hard and brittle plastic allocation properties of β phase (Tang et al. (1998)). Figure 7 presents an example of Al-Mg-Fe-Si phase located in the static fracture at the craters bottom.

6. Conclusions

The following conclusions were drawn from the conducted tests: 1. Analysis of the structure made with TIG method from 5754 aluminium alloy showed that a coarse-grained zone of approximately 1-2 mm. 2. Al-Mg-Fe-Si. Analysis of the structure of the 5754 aluminium welded joints made with TIG method showed numerous inclusions and inter-metallic phases such as Al-Mg-Fe-Si. 3. Cleavage fractures of both the shot-peened and non shot-peened specimens occurred in the recrystallization zone. 4. Shot- peening of the surface layer resulted in an almost threefold increase of roughness (from Ra = 8.812 µm to Ra = 24.514 µm) . 5. Shot-peening resulted in an increase in yield strength and elastic modulus by 20% and 29%, respectively. 6. During the shot-peening process of the surface layer, the microparticles of the material coming from stainless buckshot were transferred to the depth of approximately 70- 100 µm. 7. During the tensile tests, delimitation of the strengthen surface layer took place at the depth of approximately 150 µm. Miziolek, A., Palleschi, V., Schechter, I., 2006. Laser-induced breakdown spectroscopy. Cambridge University Press, Cambridge. Nakonieczny, A., 2002, Dynamiczna powierzchniowa obróbka plastyczna – kulowanie (shot peeling), IMP in Warsaw. Napadłek , W., Sarzyński , A., Marczak, J., 2011. Kulowanie laserowe warstwy wierzchniej stopu aluminium PA31. Inżynieria Materiałowa , 32 (4), 616-619. Orłowicz , W., Mróz M., Tupaj , M., 2006. Wpływ modyfikacji i temperatury formy na właściwości mech aniczne stopu AlSi7Mg, Archiwum odlewnictwa. 6, 18 (1/2) PAN – Katowice. Piekarski, R., 2001. Zastosowanie metod prądów wirowych do pomiaru naprężeń własnych wywołanych wybranymi obróbkami powierzchniowymi. dissertation, WIP PW in Warsaw. PN-EN 1706: 2011. Aluminium i stopy aluminium - Odlewy - Skład chemiczny i własności mechaniczne. Ravi, M., Pillai U.T.S., Pai, B.C., Damodaran, A.D., Dwarakadasa, E.S., 1998. Mechanical properties of cast Al-7Si-0.3 Mg (LM 25/356). International Journal Cast Metals Res., 11, 113-125. Sobota J., 2017. Umocnienie odkształceniowe stopów aluminium serii 6xxx, Rudy i Metale Nieżelazne Recykling , 62 (6), 20-24. Takahashi, K., Osedo, H., Suzuki, T., Fukud, S., 2018. Fatigue strength improvement of an aluminum alloy with a crack like surface defect using shot peening and cavitation peening, Engineering Fracture Mechanics, 193, 151-161. Tang, S.K., Sriharan, T., 1998. Morphology of β -AlFeSi intermetallic in Al-7Si alloy castings. Materials Science and Technology, 14, 738-742. References Jeleńkowski, J., Karpowicz, M., Mońka, G., Tacikowski, J., 2015. Influence of shot peening on the properties of aluminium alloy 7075 AW T6511 and magnesium alloy AZ31B-F. Inżynieria Powierzchni. 3, 22-27.