AZ61Mg alloy was multi directionally forged(MDFed) during decreasing temperature condition from 643 K to 483 K at a true strain rate of 3×10-3 s-1 up to cumulative strain of∑△ε=4.0 at maximum.A pass strain of...AZ61Mg alloy was multi directionally forged(MDFed) during decreasing temperature condition from 643 K to 483 K at a true strain rate of 3×10-3 s-1 up to cumulative strain of∑△ε=4.0 at maximum.A pass strain of△ε=0.8 was employed.While average grain size decreased gradually with increasing cumulative strain,the evolution of fine-grained structure strongly depended on the MDF temperature.Under the condition where the temperature was higher than the most adequate one,grain coarsening partially took place during MDF.In contrast,at lower temperature,inhomogeneous microstructure composed of the initial coarse and newly appeared fine grains was evolved.After straining over∑△ε=3.2(i.e.,over 4 passes of MDF) ,equiaxed ultrafine grains(UFGs) having average size of about and lower than 1μm were uniformly evolved.While the MDFed alloy to∑△ε=4.0 possessed relatively high hardness of HV 99,and it accepted further about 20%cold rolling almost without cracking.Because of the superior formability of the UFGed AZ61Mg alloy,the hardness was further easily raised to HV 120 by following cold rolling.展开更多
This paper mainly discussed the heat transmission rate and physical-mechanical properties of particleboard (PB) and middle density fiberboard (MDF) with different forming methods. In this experiment, both poplar and w...This paper mainly discussed the heat transmission rate and physical-mechanical properties of particleboard (PB) and middle density fiberboard (MDF) with different forming methods. In this experiment, both poplar and wheat-straw with different ratios and different shape forms were used as furnishes; UF and MDI were added to the poplar furnish and wheat-straw one, respectively. The experiment results showed that the layer-forming boards were superior to the mixture-forming boards. Under the given experimental conditions, the poplar to wheat straw ratio has no obvious influence on the mechanical properties, but has significant influence on the thickness swell (TS) of PB and MDF.展开更多
基金support given by the Light Metals Educational Foundation,Japan,and Ministry of Education,Culture,Sports and Technology,Japan,with Grant No.20560647
文摘AZ61Mg alloy was multi directionally forged(MDFed) during decreasing temperature condition from 643 K to 483 K at a true strain rate of 3×10-3 s-1 up to cumulative strain of∑△ε=4.0 at maximum.A pass strain of△ε=0.8 was employed.While average grain size decreased gradually with increasing cumulative strain,the evolution of fine-grained structure strongly depended on the MDF temperature.Under the condition where the temperature was higher than the most adequate one,grain coarsening partially took place during MDF.In contrast,at lower temperature,inhomogeneous microstructure composed of the initial coarse and newly appeared fine grains was evolved.After straining over∑△ε=3.2(i.e.,over 4 passes of MDF) ,equiaxed ultrafine grains(UFGs) having average size of about and lower than 1μm were uniformly evolved.While the MDFed alloy to∑△ε=4.0 possessed relatively high hardness of HV 99,and it accepted further about 20%cold rolling almost without cracking.Because of the superior formability of the UFGed AZ61Mg alloy,the hardness was further easily raised to HV 120 by following cold rolling.
文摘This paper mainly discussed the heat transmission rate and physical-mechanical properties of particleboard (PB) and middle density fiberboard (MDF) with different forming methods. In this experiment, both poplar and wheat-straw with different ratios and different shape forms were used as furnishes; UF and MDI were added to the poplar furnish and wheat-straw one, respectively. The experiment results showed that the layer-forming boards were superior to the mixture-forming boards. Under the given experimental conditions, the poplar to wheat straw ratio has no obvious influence on the mechanical properties, but has significant influence on the thickness swell (TS) of PB and MDF.
