Improvement of Strength and Energy Absorption Properties of Porous Aluminum Alloy with Aligned Unidirectional Pores Usin
- PDF / 1,469,451 Bytes
- 8 Pages / 593.972 x 792 pts Page_size
- 97 Downloads / 210 Views
INTRODUCTION
POROUS aluminum alloys are expected to be used as light-weight shock absorption materials owing to their superior energy absorption properties during compressive deformation.[1] However, further improvement of energy absorption per unit mass and energy absorption efficiency is required for the practical use of these alloys. Energy absorption efficiency is defined by the International Organization for Standardization 13,314 as the ratio of the energy absorption to the product of the maximum stress and strain in the measurement region.[2] Aluminum foams have high energy absorption efficiency during compression. However, the energy absorption is small owing to the low plateau stress.[3] Therefore,
TOMONORI YOSHIDA, DAIKI MUTO, and TOMOYA TAMAI are with the Department of Applied Mechanics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan. Contact e-mail: afactofl[email protected] SHINSUKE SUZUKI is with the Department of Applied Mechanics, Faculty of Science and Engineering, Waseda University and also with the Kagami Memorial Research Institute of Materials Science and Technology, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan. Manuscript submitted October 21, 2017.
METALLURGICAL AND MATERIALS TRANSACTIONS A
further increase of plateau stress is required. Lotus-type porous aluminum alloys are advantageous to achieve high plateau stress while maintaining the density. As lotus-type porous metals[4] have aligned unidirectional pores, they have higher specific strength than metallic foams under compression in the direction parallel to the pore direction.[5] However, lotus-type porous metals usually show an increase of stress even in the plateau region,[4] which reduces the energy absorption efficiency. To improve energy absorption and energy absorption efficiency, fabrication of porous aluminum alloys with compressive stress–strain curves is required, where compressive stress rapidly increases at the beginning of compression and thereafter becomes almost constant even if compressive strain increases. Optimization of the structure and material are considered to improve the compressive property of porous metals. The use of porous metal with aligned unidirectional pores is considered for structural improvement. Hyun et al. reported that a porous metal with aligned unidirectional pores has superior mechanical property in that the specific yield strength of this kind of porous metals does not decrease in the pore direction even if the porosity increases.[5] The use of A6061 processed via plastic deformation is considered for the improvement of material. This is because the compressive stress of a
material with high dislocation density rapidly increases at the beginning of compression, and thereafter, the increase of compressive stress may become gradual even if the compressive strain increases as the increase of strength via work hardening during compression is small. Therefore, fabrication of a porous aluminum alloy with aligned unidirectional pores processed via severe plastic deformation is desired.
Data Loading...
