Influence of Combined Severe Plastic Deformation and Sheet Extrusion Process on the Superplastic Formability of AA 5083
- PDF / 1,549,889 Bytes
- 10 Pages / 593.972 x 792 pts Page_size
- 73 Downloads / 195 Views
JMEPEG https://doi.org/10.1007/s11665-019-04384-6
Influence of Combined Severe Plastic Deformation and Sheet Extrusion Process on the Superplastic Formability of AA 5083 Aluminum Alloy Assessed by Free Bulge Test F. Fereshteh-Saniee, N. Fakhar, and R. Mahmudi (Submitted August 3, 2018; in revised form September 17, 2019) A combination of two forming operations is considered for producing metal sheets with improved mechanical properties. As the first operation, a newly introduced severe plastic deformation method called dual equal channel lateral extrusion (DECLE) was performed at 300 °C for different passes on the AA 5083 aluminum blocks. Following the DECLE operation, sheet extrusion was conducted to convert the bulk samples, severely deformed through various passes, into 1.8-mm-thick sheets. Mechanical properties of the processed specimens, after each step of deformation, were examined using tensile and shear punch tests. It was found that the material after three passes of DECLE and also the corresponding forwardly extruded sheet presented the greatest strength. In order to evaluate the biaxial formability of the sheets, gas bulge forming tests were conducted using a PLC-controlled gas circuit. It was shown that the material processed via three passes of DECLE operation and extrusion demonstrated the maximum biaxial superplastic formability with an effective strain associated with 400% uniaxial elongation. This sheet specimen also required the minimum forming time, coinciding with a strain rate of 4 3 1024 s21, which is higher than strain rate for the sheet extruded from the annealed sample. Keywords
AA 5083 alloy, formability, free gas bulge forming, severe plastic deformation, superplasticity
1. Introduction Steel sheets have been the best choice for producing automobile panels for many years (Ref 1). By increasing the demand for fuel-efficient vehicles, the application of lightweight alloys such as aluminum and magnesium alloys in automotive industries has been extended. Due to low formability of aluminum and magnesium alloys compared with steel sheets, the conventional processes such as stamping are not a suitable means for producing body panels (Ref 2). To address this issue, new forming technologies have been employed. These methods include super plastic forming (SPF), quick plastic forming (QPF), hydroforming, warm forming, etc. (Ref 2). Superplastic forming technology has a good situation among the other ones for manufacturing complex car body panels in automotive applications as well as for a variety of components for spacecraft and commercial airplanes in the
F. Fereshteh-Saniee, Department of Mechanical Engineering, Faculty of Engineering, Bu-Ali Sina University, Hamedan 65178, Iran; N. Fakhar, Department of Mechanical Engineering, Hamedan University of Technology, Hamedan 65155-579, Iran; and R. Mahmudi, School of Metallurgical and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran. Contact e-mails: [email protected], [email protected], [email protected], and Mahm
Data Loading...
