外加电场热处理对等径角挤压态1050铝合金组织与性能的影响

Effect of external electric field heat treatment on microstructure and properties of equal diameter angular extrusion 1050 aluminum alloy

主要采用了EBSD测试、拉伸试验和PALS测试等实验方式,研究了低温下等径角挤压的1050铝合金材料,再经不同温度(150℃~400℃)下施以电流与未施加直流电高温退火后,比较热动力学和组织结构之间的变化差异,并以实验结果为依据探讨了不同热处理条件(主要是退火温度)对材料组织性能的影响机理。研究结果表明,在退火时温为150℃~250℃时,施加电流较未施加电流的试样屈服强度减少了8.1%~11.2%,由于施加电流而导致大取向角为3°~7°的晶界结构所占比重较大,内部能量增加,大角度晶界的内部结构较不稳定;在退火环境温度为300℃~400℃下,不施以直流电退火试样比施以直流电退火试样屈服硬度的下降更加显著,而且下降速度也更快,未施以直流电的试样晶粒尺寸也会增加,迅速增加至(6.4μm~22.4μm)。而由于施加电流的试样晶粒长度较未施以直流电的尺寸小,所以屈服强度也较高。

In this paper,experimental methods such as EBSD test,tensile test and PALS test were used to study the thermal dynamics and microstructure characteristics of 1050 aluminum alloy under constant diameter angular extrusion at low temperature.After anneal⁃ing at different temperatures(150~400℃)with current and without current,the differences between thermal dynamics and microstruc⁃ture characteristics of 1050 aluminum alloy were compared.On the basis of the experimental results,the effect mechanism of different annealing temperature on the microstructure and properties of the materials was discussed.The results show that when the annealing temperature is 150~250℃,the yield strength of the sample with applied current decreases by 8.1%~11.2%compared with that without applied current.As a result,the grain boundary structure with large orientation Angle of 3°~7°accounts for a larger proportion,the in⁃ternal energy increases,and the internal structure of the grain boundary with large orientation Angle is unstable.At 300~400℃,the yield hardness of samples annealed without DC is decreased more significantly and faster than that annealed with DC.The grain size of samples annealed without DC is also increased rapidly to(6.4~22.4μm).The grain length of the sample is smaller than that of the sam⁃ple without direct current,so the yield strength is higher.