Special Issue "Superplasticity and Superplastic Forming 2012"

Guest Editor
Dr. Hengan Ou
Department of Mechanical, Materials and Manufacturing Engineering, Room B104, Coates Building, University of Nottingham, University Park, Nottingham NG7 2RD, UK
Website: http://www.nottingham.ac.uk/engineering/people/h.ou
E-Mail: h.ou@nottingham.ac.uk
Interests: process modelling and optimisation; metal forming and material processing techniques;machine system design and integration

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 800 CHF (Swiss Francs).

Title: Constitutive Modelling of Al-5083 Superplastic Aluminium Alloy with Cavitation Effects
Authors: N. Otegi ¹, L. Galdos ¹, I. Hurtado ¹, S.B. Leen ²
Affiliations: ¹ Mechanical and Manufacturing Department, Mondragon University, Loramendi, 4 20500 Arrasate – Mondragon, Spain
² Mechanical and Biomedical Engineering, NUI Galway, Ireland
Abstract: This paper describes the development of a constitutive equation set which includes the effects of cavitation-induced softening for a commercial Al-5083 superplastic aluminium alloy. The constitutive formulation adopted is a hyperbolic, mechanisms-based constitutive equation set. The development of an algorithm for multi-stage identification of the complex set of constitutive parameters is presented and this approach is applied to characterise the constitutive behaviour of the Al-5083 at 500 °C, based on constant strain-rate tensile test data. A large deformation, multiaxial formulation of the constitutive equation set is implemented and applied to finite element modelling of a bulge test forming process to characterise the cavitation evolution behaviour in the bulge test for different back pressure conditions.

Title: High Temperature Tensile Properties and Fracture Behaviour of Al-Si-Mg-Cu Alloys for Automotive Applications
Authors: Adel M. A. Mohamed ^1,2, Saleh Al kahtani ³
Affiliations: ¹ Department of Metallurgical and Materials Engineering, Faculty of Petroleum and Mining Engineering, Suez Canal University, Box 43721, Suez, Egypt
² Université du Québec à Chicoutimi, Chicoutimi, QC, G7H 2B1, Canada
³ Industrial Engineering Program, Mechanical Engineering Department, College of Engineering, Salman bin Abdulaziz University, Al Kharj, Saudi Arabia
Abstract: The high temperature tensile behaviour of 354 aluminum cast alloy was investigated in the presence of Zr and Ni. The cast alloys were given a solutionizing treatment followed by artificial aging at 190 °C for 2 h. High temperature tensile tests were conducted at various temperatures from 25 °C to 300 °C. Optical microscopy and electron probe micro-analyzer were used to study the microstructure of different intermetalic phases formed. The fractographic observations of fracture surface were analysed by scanning electron microscopy to understand the fracture mechanism. The results revealed that the intermetallics phases of (Al,Si)₃(Zr,Ti), Al₃CuNi and Al₉NiFe are the main feature in the microstructures of alloys with Zr and Ni additions. The results also indicated that the tensile strength of alloy decreases with an increase in temperature. The combined addition of 0.2 wt% Zr and 0.2 wt% Ni leads to a 30% increase in the tensile properties at 300^oC compared to the base alloy. Zr and Ni bearing phases played a vital role in the fracture mechanism of the alloys studied.
Keywords: Al-Si-Mg-Cu alloys; microstructure; high temperature tensile properties; fracture