Plastic Instabilities Induced by the Portevin - Le Châtelier Effect and Fracture Character of Deformed Mg-Li Alloys Investigated Using the Acoustic Emission Method

Archives of Metallurgy and Materials

W. Ozgowicz¹  P. Ranachowski²  Z. Ranachowski²  S. Kúdela³  S. Kúdela Jr.³  A. Piątkowski⁴  W. Wajda⁴  A. Tarasek⁴  A. Pawełek⁴  W. Skuza⁴ 

[1] INSTITUTE OF ENGINEERING MATERIALS AND BIOMATERIALS, SILESIAN UNIVERSITY OF TECHNOLOGY, 2A AKADEMICKA STR., 44-100 GLIWICE, POLAND;INSTITUTE OF FUNDAMENTAL TECHNOLOGICAL RESEARCH, POLISH ACADEMY OF SCIENCES, 5B PAWINSKIEGO STR., 02-106 WARSZAWA, POLAND;INSTITUTE OF MATERIALS AND MACHINE MECHANICS, 75 RA?IANSKA STR., 830-08 BRATISLAVA, SLOVAK REPUBLIC;INSTITUTE OF METALLURGY AND MATERIALS, POLISH ACADEMY OF SCIENCES, 25 REYMONTA STR., 30-059 KRAKÓW, POLAND

关键词: Keywords: lightweight alloys;    Acoustic Emission;    fracture;    Portevin-Le Châtelier phenomenon;    twinning;    dislocations;    shear bands;   

DOI  :  10.1515/amm-2016-0152

学科分类：金属与冶金

来源: Akademia Gorniczo-Hutnicza im. Stanislawa Staszica / University of Mining and Metallurgy

【 摘 要 】

The results of the investigation of both mechanical and acoustic emission (AE) behaviors of Mg4Li5Al and Mg4Li4Zn alloys subjected to compression and tensile tests at room temperature are compared with the test results obtained using the same alloys and loading scheme but at elevated temperatures. The main aim of the paper is to investigate, to determine and to explain the relation between plastic flow instabilities and the fracture characteristics. There are discussed the possible influence of the factors related with enhanced internal stresses such as: segregation of precipitates along grain boundaries, interaction of solute atoms with mobile dislocations (Cottrell atmospheres) as well as dislocation pile-ups which may lead to the microcracks formation due to the creation of very high stress concentration at grain boundaries. The results show that the plastic flow discontinuities are related to the Portevin-Le Châtelier phenomenon (PL effect) and they are correlated with the generation of characteristic AE pulse trains. The fractography of broken samples was analyzed on the basis of light (optical), TEM and SEM images.

【 授权许可】

Unknown