Authors: Lee, W.-S.; Lin, Y.-C.

Source: Materials Science and Technology, Volume 22, Number 5, May 2006 , pp. 571-582(12)

Publisher: Maney Publishing

Abstract:

The dynamic shear deformation behaviour and fracture characteristics of Al–Sc alloy are studied using a split Hopkinson torsional bar at shear strain rates of 800, 1800 and 2800 s⁻¹ and at temperatures of −150, 25 and 300°C. The experimental results indicate that the shear strain, shear strain rate and temperature all have a significant influence on the mechanical properties of the alloy. At constant temperature, the flow shear stress, fracture shear strain, work hardening rate, yield shear strength, work hardening coefficient, strain rate sensitivity and temperature sensitivity increase with increasing strain rate, while the activation energy decreases. Meanwhile, under a constant strain rate, the flow shear stress, work hardening rate, yielding shear strength, work hardening coefficient, strain rate sensitivity and temperature sensitivity decrease with increasing temperature while the fracture shear strain and activation energy increase. The Kobayashi and Dodd constitutive equation accurately describes the high strain rate shear plastic behaviour of Al–Sc alloy under the current test conditions. The fracture surfaces are characterised by transgranular dimpled features, which are indicative of ductile fracture. The appearance and density of these dimples are significantly dependent on the strain rate and temperature. The fracture surfaces of the gauge length section of the deformed specimen are twisted into band like features as a result of intensive localised shear deformation. This provides clear evidence of 'deformed' type shear bands. The width and microhardness of the shear band change with strain rate and temperature as a result of different work hardening effects. Specimen fracture initiates at the Al₃Sc precipitate/matrix interface. The presence of precipitates accelerates the dynamic shear fracture formation through microcracking.

Keywords: AL-SC ALLOY; DIMPLE FAILURE; STRAIN RATE AND TEMPERATURE EFFECTS; ACTIVATION ENERGY; AL3SC PRECIPITATES; DEFORMED SHEAR BAND

Document Type: Research Article

DOI: http://dx.doi.org/10.1179/174328406X86119

Publication date: 2006-05-01

More about this publication?

• Authors wishing to cite fast track papers should give the journal name and the article DOI. This will enable reference linking via CrossRef and allow forward and backward citation tracking systems to associate the fast track citation with the final journal reference.
  
  To see the complete content of Metal Science, the predecessor to Materials Science and Technology, going back to 1967, please click here.
• Editorial Board
• Information for Authors
• Subscribe to this Title
• Terms & Conditions
• Online submission site
• ingentaconnect is not responsible for the content or availability of external websites

Related content

• In this: publication
• By this: publisher
• In this Subject: Materials & Manufacturing ,  Mining & Metallurgy
• By this author: Lee, W.-S. ;  Lin, Y.-C.

Website © Publishing Technology. Article copyright remains with the publisher, society or author(s) as specified within the article.

• Terms and conditions
• Privacy policy
• Information for advertisers