Młynarczyk Piotr, Bańkowski Damian, Szwed Bartłomiej
Department of Metal Science and Manufacturing Processes, Faculty of Mechatronics and Mechanical Engineering, Kielce University of Technology, al. Tysiaclecia Panstwa Polskiego 7, 25-314 Kielce, Poland.
Materials (Basel). 2023 Oct 19;16(20):6765. doi: 10.3390/ma16206765.
The purpose of this study was to determine whether the chemical compositions of Alnico alloys had any effects on the electrical discharge machining (EDM) performance and the surface finish. This article compares the behavior of three different Alnico alloys in electrical discharge machining. The experiments were conducted under different conditions using a BP93L EDM machine (ZAP BP, Końskie, Poland), applying an additional rotary motion to the electrode. A Box-Behnken experimental design was employed to analyze the influence of three factors, i.e., the spark current, the pulse-on time, and the pulse-off time, at three levels for three Alnico alloys. The material removal rate (MRR) was calculated for the different process parameters. After the EDM, the surface roughness was studied using a Talysurf CCI Lite non-contact profiler (Taylor-Hobson, Leicester, UK). The next step of the experiments involved preparing metallographic specimens to be observed by means of scanning electron microscopy (SEM) and optical microscopy (OM). Measurements of the nanohardness were also performed. The experimental data were then analyzed using Statistica software version 10 (64-bit) to determine and graphically represent the relationships between the input and output parameters for the three Alnico alloys. The chemical compositions of the Alnico alloys affected the thickness of the white layer (higher cobalt content, lower white layer thickness) and the material removal rate. The higher the cobalt content, the thinner the white layer and the lower the material removal efficiency. Moreover, the cobalt content in Alnico alloys influenced the shape of the precipitates; these ranged from spheroidal (13% Co) to mix-shaped (21.3% Co) to flake-shaped (32.2%). The hardness of the resulting white layer was 874 HV at10 mN.
本研究的目的是确定铝镍钴合金的化学成分是否对放电加工（EDM）性能和表面光洁度有任何影响。本文比较了三种不同铝镍钴合金在放电加工中的表现。实验在不同条件下使用BP93L电火花加工机床（ZAP BP，波兰科尼斯克）进行，电极施加额外的旋转运动。采用Box-Behnken实验设计来分析火花电流、脉冲导通时间和脉冲关断时间这三个因素在三个水平下对三种铝镍钴合金的影响。针对不同的工艺参数计算材料去除率（MRR）。电火花加工后，使用Talysurf CCI Lite非接触轮廓仪（泰勒-霍普森，英国莱斯特）研究表面粗糙度。实验的下一步是制备金相试样，以便通过扫描电子显微镜（SEM）和光学显微镜（OM）进行观察。还进行了纳米硬度测量。然后使用Statistica软件10版本（64位）分析实验数据，以确定并以图形方式表示三种铝镍钴合金输入和输出参数之间的关系。铝镍钴合金的化学成分影响白层的厚度（钴含量越高，白层厚度越低）和材料去除率。钴含量越高，白层越薄，材料去除效率越低。此外，铝镍钴合金中的钴含量影响析出物的形状；这些析出物的形状从球形（13% Co）到混合形（21.3% Co）再到片状（32.2%）。在10 mN力下，所得白层的硬度为874 HV。
