在应变速率为0.1、0.01、0.001s^(-1)和变形温度400、450、500℃条件下采用热模拟试验机对Al-11.5Si-1.6Mg-3.5Cu合金进行了等温热压缩试验,并采用动态材料模型(Dynamic Material Modeling, DMM)绘制材料的热加工图,预测了所设计的钎料...在应变速率为0.1、0.01、0.001s^(-1)和变形温度400、450、500℃条件下采用热模拟试验机对Al-11.5Si-1.6Mg-3.5Cu合金进行了等温热压缩试验,并采用动态材料模型(Dynamic Material Modeling, DMM)绘制材料的热加工图,预测了所设计的钎料合金Al-11.5Si-1.6Mg-3.5Cu与芯材铝合金AA3003的变形机制,从而得到钎料合金和芯材合金共同适合的加工窗口,避免复合轧制过程中出现材料开裂、变形不匹配等问题,缩短试验时间。试验结果表明,当变形温度在400~500℃,应变速率范围为0.001s^(-1)~0.1s^(-1),Al-11.5Si-1.6Mg-3.5Cu合金与芯材合金AA3003在高温变形时不会出现失稳现象,并且在较高的温度和较低的应变速率下比较适合材料的成形加工。展开更多
The non-heat-treatable AA3003-H18 plates were joined by friction stir welding（FSW） to achieve a proper joint by optimizing the welding parameters.For this purpose,the effects of heat input on microstructure and mech...The non-heat-treatable AA3003-H18 plates were joined by friction stir welding（FSW） to achieve a proper joint by optimizing the welding parameters.For this purpose,the effects of heat input on microstructure and mechanical properties of the welded samples were investigated by changing the ratios of rotational speed（800-1200 r/min） to travel speed（40-100 mm/min）（w/v）.It was revealed that the grain growth rate was strongly increased with the increase of the heat input by rotational speed at constant travel speed,while the grain growth rate was slightly increased with the increase of the heat input by travel speed at constant rotational speed.Subsequently,hardness reduction was observed in the stir zone at higher rotational speed compared with that at lower one.An interesting observation was that various welding parameters do not have noticeable effect on the tensile strength of the FSW joints.Also,it has been observed that the fracture location of tensile test specimens was placed in the heat-affected zone（HAZ）on the advancing side at lower travel speed,while at higher travel speed,it was placed at the HAZ/thermomechanical affected zone（TMAZ） interface on the retreating side.展开更多
The effect of concurrent precipitation on recrystallization textures in AA 3003 aluminum alloys was investigated using X-ray diffraction and electron backscattering diffraction（EBSD） analyses. A weak recrystallizati...The effect of concurrent precipitation on recrystallization textures in AA 3003 aluminum alloys was investigated using X-ray diffraction and electron backscattering diffraction（EBSD） analyses. A weak recrystallization texture was observed in the AA 3003 alloy annealed at 783 K due to the high annealing temperature. Under the same conditions, extremely high P {011 } （ 111 ） recrystallization textures were detected in the AA 3003 alloy added with 0. 39% Sc. Based on the EBSD results, no intensely preferential orientation nucleation of recrystallization grains was observed in the early stage of recrystallizafion for both alloys. However, concurrent precipitation strongly retarded the growth of recrystallization grains, except for P nucleation sites, thereby conferring an apparent initial growth advantage for P nucleation sites compared with other nucleation sites. Therefore, a sharp P {011 } 〈 111 〉 texture appeared in concurrently precipitated AA 3003 alloys.展开更多
Ultrasonic welding process can be used for bonding metal foils which is the fundament of ultrasonic consolidation （UC）. UC process can be used to embed reinforcement fibres such as SiC fibres within an aluminum matr...Ultrasonic welding process can be used for bonding metal foils which is the fundament of ultrasonic consolidation （UC）. UC process can be used to embed reinforcement fibres such as SiC fibres within an aluminum matrix materials. In this research we are investigating the phenomena occurring in the microstructure of the parts during ultrasonic welding process to obtain better understanding about how and why the process works. High-resolution electron backscatter diffraction （ EBSD ） is used to study the effects of the vibration on the evolution of microstructure in AA3003. The inverse pole figures （IPF） and the correlated misorientation angle distribution of the mentioned samples are obtained. The characteristics of the crystallographic orientation, the grain structure and the grain boundary are analyzed to find the effect of ultrasonic vibration on the microstructure and microtexture of the bond. The ultrasonic vibration will lead to exceptional refinement of grains to a micron level along the bond area and affect the crystallographic orientation. Ultrasonic vibration results in a very weak texture. Plastic flow occurs in the grain after welding process and there is additional plastic flow around the fibre which leads to the fibre embedding.展开更多
文摘在应变速率为0.1、0.01、0.001s^(-1)和变形温度400、450、500℃条件下采用热模拟试验机对Al-11.5Si-1.6Mg-3.5Cu合金进行了等温热压缩试验,并采用动态材料模型(Dynamic Material Modeling, DMM)绘制材料的热加工图,预测了所设计的钎料合金Al-11.5Si-1.6Mg-3.5Cu与芯材铝合金AA3003的变形机制,从而得到钎料合金和芯材合金共同适合的加工窗口,避免复合轧制过程中出现材料开裂、变形不匹配等问题,缩短试验时间。试验结果表明,当变形温度在400~500℃,应变速率范围为0.001s^(-1)~0.1s^(-1),Al-11.5Si-1.6Mg-3.5Cu合金与芯材合金AA3003在高温变形时不会出现失稳现象,并且在较高的温度和较低的应变速率下比较适合材料的成形加工。
基金the research board of Sharif University of Technology for the financial supportthe provision of the research facilities used in this work
文摘The non-heat-treatable AA3003-H18 plates were joined by friction stir welding（FSW） to achieve a proper joint by optimizing the welding parameters.For this purpose,the effects of heat input on microstructure and mechanical properties of the welded samples were investigated by changing the ratios of rotational speed（800-1200 r/min） to travel speed（40-100 mm/min）（w/v）.It was revealed that the grain growth rate was strongly increased with the increase of the heat input by rotational speed at constant travel speed,while the grain growth rate was slightly increased with the increase of the heat input by travel speed at constant rotational speed.Subsequently,hardness reduction was observed in the stir zone at higher rotational speed compared with that at lower one.An interesting observation was that various welding parameters do not have noticeable effect on the tensile strength of the FSW joints.Also,it has been observed that the fracture location of tensile test specimens was placed in the heat-affected zone（HAZ）on the advancing side at lower travel speed,while at higher travel speed,it was placed at the HAZ/thermomechanical affected zone（TMAZ） interface on the retreating side.
基金The National Natural Science Foundation of China(No.51201031)the Natural Science Foundation of Jiangsu Province(No.BK2011615)the Transformation Program of Science and Technology Achievements of Jiangsu Province(No.BA2011024)
文摘The effect of concurrent precipitation on recrystallization textures in AA 3003 aluminum alloys was investigated using X-ray diffraction and electron backscattering diffraction（EBSD） analyses. A weak recrystallization texture was observed in the AA 3003 alloy annealed at 783 K due to the high annealing temperature. Under the same conditions, extremely high P {011 } （ 111 ） recrystallization textures were detected in the AA 3003 alloy added with 0. 39% Sc. Based on the EBSD results, no intensely preferential orientation nucleation of recrystallization grains was observed in the early stage of recrystallizafion for both alloys. However, concurrent precipitation strongly retarded the growth of recrystallization grains, except for P nucleation sites, thereby conferring an apparent initial growth advantage for P nucleation sites compared with other nucleation sites. Therefore, a sharp P {011 } 〈 111 〉 texture appeared in concurrently precipitated AA 3003 alloys.
基金Acknowledgement The authors wish to thank the financial support for this research from the National Natural Science Foundation of China （Grant No. 50865007） and the Natural Science Foundation of Jiangxi Province （No. 2007GQC1825）.
文摘Ultrasonic welding process can be used for bonding metal foils which is the fundament of ultrasonic consolidation （UC）. UC process can be used to embed reinforcement fibres such as SiC fibres within an aluminum matrix materials. In this research we are investigating the phenomena occurring in the microstructure of the parts during ultrasonic welding process to obtain better understanding about how and why the process works. High-resolution electron backscatter diffraction （ EBSD ） is used to study the effects of the vibration on the evolution of microstructure in AA3003. The inverse pole figures （IPF） and the correlated misorientation angle distribution of the mentioned samples are obtained. The characteristics of the crystallographic orientation, the grain structure and the grain boundary are analyzed to find the effect of ultrasonic vibration on the microstructure and microtexture of the bond. The ultrasonic vibration will lead to exceptional refinement of grains to a micron level along the bond area and affect the crystallographic orientation. Ultrasonic vibration results in a very weak texture. Plastic flow occurs in the grain after welding process and there is additional plastic flow around the fibre which leads to the fibre embedding.
