The correct use of the conical interlocksin the automobile mold can keep the mold stabilityunchanged, and the mold stability does not change withthe parallel accuracy of the bed. In this way, repeatedresearch and deve...The correct use of the conical interlocksin the automobile mold can keep the mold stabilityunchanged, and the mold stability does not change withthe parallel accuracy of the bed. In this way, repeatedresearch and development and repeated debug areavoided to obtain stable quality parts.展开更多
The dissimilar material resistance spot welding of galvanized high strength steel and aluminum alloy had been conducted. The welded joint exhibited a thin reaction layer composed of Fe2Al5 and Fe4Al13 phases at steel/...The dissimilar material resistance spot welding of galvanized high strength steel and aluminum alloy had been conducted. The welded joint exhibited a thin reaction layer composed of Fe2Al5 and Fe4Al13 phases at steel/aluminum interface. The welded joint presented a tensile shear load of 3.3 kN with an aluminum alloy nugget diameter of 5.7 mm. The interfacial failure mode was observed for the tensile shear specimen and fracture occurred at reaction layer and aluminum alloy fusion zone beside the interface. The reaction layer with compounds was the main reason for reduction of the welded joint mechanical property.展开更多
The power law model is the most widely used model for the rheological behavior of semi-solid metals(SSMs)in the numerical simulation of semi-solid processing.However,it is still not known why the anomalous negative fl...The power law model is the most widely used model for the rheological behavior of semi-solid metals(SSMs)in the numerical simulation of semi-solid processing.However,it is still not known why the anomalous negative flow exponent exists in the power law model for SSMs and its influence on the simulation.In this research,the rheological behavior of semi-solid Al-7Si-0.3Mg aluminum alloy is experimentally studied followed by modeling.The power law model fitting results show flow curves deviate from the experimental data and negative flow exponents,which are physically nonsensical and inapplicable to the simulation of SSMs flow proved by hydrodynamic analysis.This drawback of the power law model stems from neglecting the yield stress of SSMs.By contrast,the model referring Herschel-Bulkley(HB)theory which takes yield stress into consideration has reasonable flow exponent and yields good agreement between the fitting and experimental results.Furthermore,the simulation of die filling process is conducted,suggesting that the power law model over-optimistically predicts the tendency of blistering and misrun defects at low temperature and high filling velocity during semi-solid processing.展开更多
文摘The correct use of the conical interlocksin the automobile mold can keep the mold stabilityunchanged, and the mold stability does not change withthe parallel accuracy of the bed. In this way, repeatedresearch and development and repeated debug areavoided to obtain stable quality parts.
文摘The dissimilar material resistance spot welding of galvanized high strength steel and aluminum alloy had been conducted. The welded joint exhibited a thin reaction layer composed of Fe2Al5 and Fe4Al13 phases at steel/aluminum interface. The welded joint presented a tensile shear load of 3.3 kN with an aluminum alloy nugget diameter of 5.7 mm. The interfacial failure mode was observed for the tensile shear specimen and fracture occurred at reaction layer and aluminum alloy fusion zone beside the interface. The reaction layer with compounds was the main reason for reduction of the welded joint mechanical property.
基金supported by the National Key Research Project(No.2016YFB0300901)。
文摘The power law model is the most widely used model for the rheological behavior of semi-solid metals(SSMs)in the numerical simulation of semi-solid processing.However,it is still not known why the anomalous negative flow exponent exists in the power law model for SSMs and its influence on the simulation.In this research,the rheological behavior of semi-solid Al-7Si-0.3Mg aluminum alloy is experimentally studied followed by modeling.The power law model fitting results show flow curves deviate from the experimental data and negative flow exponents,which are physically nonsensical and inapplicable to the simulation of SSMs flow proved by hydrodynamic analysis.This drawback of the power law model stems from neglecting the yield stress of SSMs.By contrast,the model referring Herschel-Bulkley(HB)theory which takes yield stress into consideration has reasonable flow exponent and yields good agreement between the fitting and experimental results.Furthermore,the simulation of die filling process is conducted,suggesting that the power law model over-optimistically predicts the tendency of blistering and misrun defects at low temperature and high filling velocity during semi-solid processing.
