有色金属工程（有色金属（中英文））

通过施加不同励磁电流的脉冲磁场，探究了5A06铝合金凝固组织在励磁电流150～300 A脉冲磁场作用下的演变规律(励磁电流分别为285、220和155 A)。利用蔡司金相显微镜(OM)、场发射扫描电子显微镜(SEM)和X射线衍射(XRD)等多种表征技术，对5A06铝合金的微观组织形貌、相组成进行分析，使用维氏硬度计、钢研纳克拉伸机进行力学实验。结果表明：当励磁电流为155 A时，晶粒细化效果最佳，由未施加磁场的原样晶粒尺寸62.95μm，降低至45.26μm，较原样降低28.10%。脉冲磁场使粗大的不规则晶界析出相Al_3Mg₂相、Al₆(FeMn)相转变为细小的球状，原样的析出相尺寸均值为10.81??m²，励磁电流155 A试样的析出相尺寸均值为7.68??m²，相比原样减小28.95%。硬度值由原样的77.82 HV增加到82.52 HV，提升6%；抗拉强度由原样的312 MPa增加到362 MPa，提升16%。

In order to further enhance the comprehensive performance of 5A06 aluminum alloy,this experiment was conducted. 5A06 aluminum alloy features low density,light weight and high specific strength,and is widely used in aerospace,shipbuilding and other fields. However,it has problems such as uneven grain size and coarse precipitated phase morphology,which limit the improvement of its performance. By applying pulsed magnetic fields with different excitation currents,the influence of pulsed magnetic fields on the evolution law of the solidification structure and mechanical properties of 5A06 aluminum alloy was explored,providing experimental data for optimizing the performance of 5A06 aluminum alloy. Based on the characteristic that 5A06 aluminum alloy has a higher Mg content compared to other aluminum alloys,combined with the previous research data,a pulsed magnetic field with an excitation current applied within the range of 150–300 A(specifically 285 A,220 A and 155 A were selected) was designed to treat 5A06 aluminum alloy,and a comparison was made with the original sample without the application of the magnetic field. The other parameters of the pulsed magnetic field were set as follows:frequency 20 Hz,duty cycle 20%,and processing time 60 s. Metallographic specimens and tensile specimens were prepared. The microstructure morphology of the alloy was observed by using Zeiss metallographic microscope(OM) and field emission scanning electron microscope(SEM). The phase composition of 5A06 aluminum alloy was analyzed by X-ray diffraction(XRD) and EDS energy dispersive spectroscopy. Hardness tests and tensile tests were carried out using Vickers hardness testers and steel Research Institute NAK tensile machines to analyze the microstructure(fracture morphology) and mechanical properties of the alloy. The experimental results show that when the excitation current is 155 A,the grain refinement effect of the alloy is the most prominent. The grain size of the alloy decreases from 62.95 μm of the original sample to 45.26 μm,with a reduction rate of 28.10%. Pulsed magnetic field causes the coarse and irregular grain boundary precipitated phases Al₃ Mg₂ and Al₆(FeMn) to transform into fine spheres,thereby reducing the adverse effects of the precipitated phases and improving the plasticity and elongation of 5A06 aluminum alloy. The average size of the precipitated phase with an excitation current of 155 A was 7.68 μm²,which was 28.95% smaller than that of the precipitated phases without a pulsed magnetic field,which was 10.81 μm². In terms of mechanical properties,the hardness value increased from 77.82 HV of the original sample to 82.52 HV,with an increase of 6%. The tensile strength increased from 312 MPa to 362 MPa,with an increase of 16%. It can be seen that the effect of the pulsed magnetic field is obvious. Under the action of pulsed magnetic field,the microstructure of 5A06 aluminum alloy was significantly improved,the morphology of the precipitated phase was standardized,and it tended to spheroidize. The grain refinement effect was obvious,thereby effectively enhancing the hardness,tensile strength,yield strength and other mechanical properties of 5A06 aluminum alloy. This paper,in combination with the previous research results,discusses the influence of electromagnetic energy introduced by the pulsed magnetic field on the internal energy of the 5A06 aluminum alloy melt,and analyzes the influence of electromagnetic energy and the Lorentz force generated in the melt on the melt. For the performance optimization of 5A06 aluminum alloy,the relevant process parameters of pulsed magnetic field are provided as references. Subsequently,in-depth research can be carried out around the parameters of pulsed magnetic field and aluminum alloys with specific compositions to study the laws of microstructure evolution and further enrich the basic experimental data of the application of pulsed magnetic field technology in the high-performance preparation of aluminum alloys.