Analysis and Evaluation of Novel Al-Mg-Sc-Zr Aerospace Alloy Strip Produced Using the Horizontal Single Belt Casting (HS
- PDF / 1,511,111 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 68 Downloads / 175 Views
I.
INTRODUCTION
NEAR net shape casting (NNSC) is a promising area for casting research in process metallurgy. It refers to casting processes that produce as-cast products that are closer to the thicknesses of finished products. This minimizes post-casting size reduction and finishing steps. Strip casting, and specifically horizontal single belt casting (HSBC), is a new form of NNSC process for the production of hot-rolled metallic strips. The HSBC process is a prime candidate for the future of sheet metal production due to its low cost, reduced energy needs, and reduced pollution output compared with conventional casting processes. In the current study, we used a novel aluminum alloy that is based on the medium-strength 5000-series containing magnesium, which exhibits high ductility, good corrosion resistance, and good weldability. The additions of scandium and zirconium to these alloys can substantially improve their strength, workability, and high-temperature resistance.[1–4] As a result, Al-Mg-Sc-Zr-based alloys may perform well in aerospace applications.[5] In the Al-Mg-Sc-Zr system, Mg is present mainly in its dissolved state, which generates solution strengthening. Meanwhile, Sc and Zr additions provide strengthening through the formation of Al3(Sc,Zr) precipitates and by grain refinement. The high mechanical strength of this system results mostly
SA GE, Ph.D. Student, MIHAIELA ISAC, Associate Director, and RODERICK I.L. GUTHRIE, Director, are with the McGill Metals Processing Centre (MMPC), McGill University, 3610 University Street, Montreal, QC H3A 2B2, Canada. Contact e-mail: roderick.guthrie@ mcgill.ca MERT CELIKIN, formerly Post-Doctoral Fellow, with the McGill Metals Processing Centre (MMPC), McGill University, Montreal, is now with the Institut National de la Recherche Scientifique (INRS), Montreal, QC, Canada. Manuscript submitted December 8, 2014. METALLURGICAL AND MATERIALS TRANSACTIONS B
from ‘‘Orowan Strengthening’’ via dislocation pinning resistance.[1–6] Furthermore, Al3(Sc,Zr) precipitates also delay recrystallization during hot working, which allows alloys based on the Al-Mg-Sc-Zr system to maintain their strength at higher temperatures, compared with equivalent alloys without Sc/Zr.[6] As the main focus in most studies has been precipitation hardening, gravity/ ingot casting has typically been used as the processing route, followed by heat treatment. In the current study, a novel alloy, with nominal composition Al-4Mg-0.6Sc0.12Zr (wt pct), was cast using the HSBC process, on a pilot-scale caster and a HSBC simulator system. We aimed to evaluate the suitability of the HSBC process for the production of this alloy and to investigate its advantages over conventionally produced as-cast AlMg-Sc-Zr alloy strips. To this end, we performed microstructural analysis and mechanical tests on the as-cast and heat-treated alloy strips produced by the HSBC process, and compared them to those produced by the Direct Chill casting process. II.
PROCESS OVERVIEW AND EXPERIMENTAL PROCEDURE
A. The HSBC Production o
Data Loading...
