论文部分内容阅读
目的利用强流脉冲电子束改性Al-17.5Si-0.3Nd合金表面,提高合金表面的显微硬度。方法通过场发射扫描电镜(FESEM)、电子探针(EPMA)、X射线衍射仪(XRD)以及维氏显微硬度计等一系列先进的检测手段,对改性后合金表面的微观形貌和性能变化进行研究。结果 SEM以及EPMA分析结果显示强流脉冲电子束处理后,合金表面形成了铝基体以及无微裂纹的晕圈结构,并且改性后合金表面上各种元素分布均匀。XRD结果显示强流脉冲电子束处理后,合金表面无新相形成,所有衍射峰发生了宽化以及偏移现象。随着脉冲次数的增加,衍射峰先向高角度偏移,后向低角度偏移。其中,5次脉冲试样的偏移角度最大。另外,显微硬度测试结果显示,铝基体的硬度随脉冲次数增加而递增,硬度值由原始样品的534.95 MPa增加到25次脉冲的1258.59 MPa;相对地,晕圈组织的硬度随脉冲次数的增加而递减,硬度值由原始样品的10 067.7 MPa下降到25次脉冲的1390.29 MPa。结论强流脉冲电子束改性后的合金表面晶粒细化显著,表面硬度总体上有所提高。
Objective To improve the microhardness of Al-17.5Si-0.3Nd alloy by pulsed electron beam. Methods A series of advanced detection methods, such as field emission scanning electron microscopy (FESEM), electron probe (EPMA), X-ray diffraction (XRD) and Vickers microhardness tester, Performance changes were studied. Results The SEM and EPMA results showed that the aluminum matrix and the halo structure without microcracking were formed on the surface of the alloy after the high-current pulsed electron beam treatment, and the various elements on the surface of the alloy were uniformly distributed. XRD results show that there is no new phase formed on the surface of the alloy and all the diffraction peaks are broadened and shifted after the high-current pulsed electron beam treatment. As the number of pulses increases, the diffraction peak is shifted to a high angle and then to a low angle. Among them, the five pulse samples have the largest offset angle. In addition, the results of microhardness test showed that the hardness of aluminum matrix increased with the increase of pulse number, and the hardness value increased from 534.95 MPa of the original sample to 1258.59 MPa of 25 pulses. On the contrary, the hardness of halo tissue increased with pulse number While decreasing, the hardness decreased from 10 067.7 MPa of the original sample to 1390.29 MPa of 25 pulses. Conclusion The grain refinement of the alloy surface after high-intensity pulsed electron beam modification is remarkable, and the surface hardness is generally improved.