Aluminum foam sandwich was prepared by rolling-bonding/powder metallurgical foaming technology, and the effects of rolling on bond strength of face sheet/powders and powder density were studied. Moreover, the foaming ...Aluminum foam sandwich was prepared by rolling-bonding/powder metallurgical foaming technology, and the effects of rolling on bond strength of face sheet/powders and powder density were studied. Moreover, the foaming agent, TiH2, was heat treated and a certain amount of Mg was added into powder in an attempt to understand how the stability and uniformity of foam was improved. The experimental results show that the foaming precursors with ideal quality were obtained by rolling-bonding process. When rolling reduction is 67%, the consistency of powders reach to 99.87%. Throughout consideration of the bonding of face sheet/ core layer powders and deformation characteristic of powders, the optimum rolling reduction is 60%-70%. Cracks and drainage during foaming were inhibited by heat treatment of foaming agent TiH2 and the addition of a certain amount of Mg. The optimum heat treatment way of TiH2 is that heat preserving 1 hour at 450 ℃; the amount of adding Mg is 1wt%.展开更多
Strain rate sensitivity and deformation mechanism of integral-forming aluminum foam sandwich(IFAFS)under quasi-static and dynamic compression were investigated.Split Hopkinson pressure bar experiments with high-speed ...Strain rate sensitivity and deformation mechanism of integral-forming aluminum foam sandwich(IFAFS)under quasi-static and dynamic compression were investigated.Split Hopkinson pressure bar experiments with high-speed video cameras were conducted to analyze strain rate dependency and actual deformation mechanism of IFAFS.X-ray microtomography technique(Micro-CT)based on 3D finite element(FE)was used to study stress and plastic strain contours of IFAFS sample and to predict stress distribution and deformation history under both dynamic and quasi-static loadings.Micro-inertia effect of typical cell structures was quantitatively analyzed by FE simulation.The results showed that IFAFS is sensitive to strain rate where the deformation mode under dynamic loading is different from that observed under quasi-static loading.With strain rate increasing,good metallurgical bonding of face sheet and foam core layer contributed to improving the elastic modulus and peak stress of IFAFS.Furthermore,finite element model confirmed that micro-inertia effect of IFAFS can be ignored during dynamic loading.展开更多
Foam materials have many attractive properties because of their low-weight and cell structure. By sandwiches with an aluminum-foam core, it is possible to obtain higher structural stiffness and rigidity, maintain stab...Foam materials have many attractive properties because of their low-weight and cell structure. By sandwiches with an aluminum-foam core, it is possible to obtain higher structural stiffness and rigidity, maintain stability against buckling and additionally make use of the high energy dissipation capability of the bare foams. The most obvious and straightforward one is adhesive bonding of pre-fabricated aluminum foams and metal face sheets. A new manufacture processing is proposed for preparation of aluminum alloy foam sandwich, ie., Al-plate/mixed element powder/ Al-plate are sandwich rolled together by a large reduction in pass, which is then foamed in heating furnace to manufacture end-use product. Aluminum alloy foam sandwich is obtained in this experiment. The experimental results showed that the process of rolling interface belongs to mechanical bonding, whose mechanism is film theory. While interface bonding belong to metallurgy bonding in the process of foaming, Al atom interdiffused in the interface, and no new phase was generated in the foaming process of aluminum face sheet/powders precursor. Bending fatigue test results showed that the bonding force of the foamed sandwich interface is very high, in fatigue test fracture occurred in the whole foam aluminum sandwich panels and Al/foam core interface was not laminated.展开更多
Effects of face-sheet thickness and core thickness of sandwich panels, and shape of projectiles on the penetration resistance of sandwich panels were discussed, while typical pen- etration failure modes were presented...Effects of face-sheet thickness and core thickness of sandwich panels, and shape of projectiles on the penetration resistance of sandwich panels were discussed, while typical pen- etration failure modes were presented. It was shown that the anti-penetration performance of sandwich panels was enhanced with the increase of face-sheet or core thickness; The penetration resistance of sandwich panels was shown to be strongest to blunt-shaped projectile impacts, weaker to hemispherical-nose-shaped projectile impacts, and weakest to conical-shaped projectile impacts. The corresponding numerical simulation was carried out using the finite element code LS-DYNA V970. Numerical results showed that the penetration time decreased with the increase of projectile impact velocity.展开更多
基金Funded by the National Natural Science Foundation of China(No.50704012)the Science and Technology Foundation of Shenyang (No. F10-205-1-59)
文摘Aluminum foam sandwich was prepared by rolling-bonding/powder metallurgical foaming technology, and the effects of rolling on bond strength of face sheet/powders and powder density were studied. Moreover, the foaming agent, TiH2, was heat treated and a certain amount of Mg was added into powder in an attempt to understand how the stability and uniformity of foam was improved. The experimental results show that the foaming precursors with ideal quality were obtained by rolling-bonding process. When rolling reduction is 67%, the consistency of powders reach to 99.87%. Throughout consideration of the bonding of face sheet/ core layer powders and deformation characteristic of powders, the optimum rolling reduction is 60%-70%. Cracks and drainage during foaming were inhibited by heat treatment of foaming agent TiH2 and the addition of a certain amount of Mg. The optimum heat treatment way of TiH2 is that heat preserving 1 hour at 450 ℃; the amount of adding Mg is 1wt%.
基金This work was supported by Key R&D Program of Hebei Province(19251013D)Special Fund for Military-civilian Integration Development of Hebei Province,Provincial School Science and Technology Cooperation Development Fund Project of Hebei Province and National Students Innovation and Entrepreneurship Training Program(No.X202110080054).The authors gratefully acknowledge the 3D visualization analysis provided by Tianjin Sanying Precision Instrument Co.,Ltd.
文摘Strain rate sensitivity and deformation mechanism of integral-forming aluminum foam sandwich(IFAFS)under quasi-static and dynamic compression were investigated.Split Hopkinson pressure bar experiments with high-speed video cameras were conducted to analyze strain rate dependency and actual deformation mechanism of IFAFS.X-ray microtomography technique(Micro-CT)based on 3D finite element(FE)was used to study stress and plastic strain contours of IFAFS sample and to predict stress distribution and deformation history under both dynamic and quasi-static loadings.Micro-inertia effect of typical cell structures was quantitatively analyzed by FE simulation.The results showed that IFAFS is sensitive to strain rate where the deformation mode under dynamic loading is different from that observed under quasi-static loading.With strain rate increasing,good metallurgical bonding of face sheet and foam core layer contributed to improving the elastic modulus and peak stress of IFAFS.Furthermore,finite element model confirmed that micro-inertia effect of IFAFS can be ignored during dynamic loading.
文摘Foam materials have many attractive properties because of their low-weight and cell structure. By sandwiches with an aluminum-foam core, it is possible to obtain higher structural stiffness and rigidity, maintain stability against buckling and additionally make use of the high energy dissipation capability of the bare foams. The most obvious and straightforward one is adhesive bonding of pre-fabricated aluminum foams and metal face sheets. A new manufacture processing is proposed for preparation of aluminum alloy foam sandwich, ie., Al-plate/mixed element powder/ Al-plate are sandwich rolled together by a large reduction in pass, which is then foamed in heating furnace to manufacture end-use product. Aluminum alloy foam sandwich is obtained in this experiment. The experimental results showed that the process of rolling interface belongs to mechanical bonding, whose mechanism is film theory. While interface bonding belong to metallurgy bonding in the process of foaming, Al atom interdiffused in the interface, and no new phase was generated in the foaming process of aluminum face sheet/powders precursor. Bending fatigue test results showed that the bonding force of the foamed sandwich interface is very high, in fatigue test fracture occurred in the whole foam aluminum sandwich panels and Al/foam core interface was not laminated.
基金supported by the National Natural Science Foundation of China(Nos.52071069,U1332110)the Liaoning Revitalization Talents Program,China(No.XLYC1902097)。
基金Project supported by the National Natural Science Foundation of China(Nos.11172196,11572214 and 11402216)the Top Young Academic Leaders of Higher Learning Institutions of Shanxi and the opening foundation for State Key Laboratory of Explosion Science and Technology and the State Key Laboratory of Traction Power(No.2014TPL T09)
文摘Effects of face-sheet thickness and core thickness of sandwich panels, and shape of projectiles on the penetration resistance of sandwich panels were discussed, while typical pen- etration failure modes were presented. It was shown that the anti-penetration performance of sandwich panels was enhanced with the increase of face-sheet or core thickness; The penetration resistance of sandwich panels was shown to be strongest to blunt-shaped projectile impacts, weaker to hemispherical-nose-shaped projectile impacts, and weakest to conical-shaped projectile impacts. The corresponding numerical simulation was carried out using the finite element code LS-DYNA V970. Numerical results showed that the penetration time decreased with the increase of projectile impact velocity.
