Kannan Sathish, Pervaiz Salman, Jahan Muhammad Pervej, Venkatraghaven DoraiSwamy
Department of Mechanical Engineering, American University of Sharjah, Sharjah 26666, UAE.
Department of Mechanical and Industrial Engineering, Rochester Institute of Technology-Dubai Campus, Dubai 341055, UAE.
Materials (Basel). 2020 Sep 15;13(18):4094. doi: 10.3390/ma13184094.
Machined surface quality and integrity affect the corrosion performance of AZ31 magnesium composites. These novel materials are preferred for temporary orthopedic and vascular implants. In this paper, the drilling performance of AZ31-magnesium reinforced with hollow alumina microsphere syntactic foam under LN2 cryogenic, dry, and Almag Oil is presented. Cutting tests were conducted using TiAlN physical vapor deposition (PVD) coated multilayer carbide and K10 uncoated carbide twist drills. AZ31 magnesium matrices were reinforced with hollow alumina ceramic microspheres with varying volume fractions (5%, 10%, 15%) and average bubble sizes. Experimental results showed that the drilling thrust forces increased by 250% with increasing feed rate (0.05 to 0.6 mm/tooth) and 46% with the increasing volume fraction of alumina microspheres (5% to 15%). Cryogenic machining generated 45% higher thrust forces compared to dry and wet machining. The higher the volume fraction and the finer the average size of hollow microspheres, the higher were the thrust forces. Cryogenic machining (0.42 µm) produced a 75% improvement in surface roughness (Ra) values compared to wet machining (1.84 µm) with minimal subsurface machining-induced defects. Surface quality deteriorated by 129% with an increasing volume fraction of alumina microspheres (0.61 µm to 1.4 µm). Burr height reduction of 53% was achieved with cryogenic machining (60 µm) compared to dry machining (130 µm). Overall, compared to dry and wet machining methods, cryogenic drilling can be employed for the machining of AZ31 magnesium syntactic foams to achieve good surface quality and integrity.
机械加工表面质量和完整性会影响AZ31镁基复合材料的耐腐蚀性能。这些新型材料是临时骨科和血管植入物的首选。本文介绍了空心氧化铝微球复合泡沫增强AZ31镁合金在液氮低温、干式和Almag油润滑条件下的钻孔性能。使用TiAlN物理气相沉积（PVD）涂层多层硬质合金和K10未涂层硬质合金麻花钻进行了切削试验。AZ31镁基体用不同体积分数（5%、10%、15%）和平均气泡尺寸的空心氧化铝陶瓷微球增强。实验结果表明，随着进给速度从0.05增加到0.6mm/齿，钻孔轴向力增加了250%，随着氧化铝微球体积分数从5%增加到15%，轴向力增加了46%。与干式和湿式加工相比，低温加工产生的轴向力高45%。空心微球的体积分数越高，平均尺寸越细，轴向力越高。与湿式加工（1.84µm）相比，低温加工（0.42µm）使表面粗糙度（Ra）值提高了75%，且加工引起的亚表面缺陷最小。随着氧化铝微球体积分数增加（从0.61µm到1.4µm），表面质量恶化了129%。与干式加工（130µm）相比，低温加工（60µm）使毛刺高度降低了53%。总体而言，与干式和湿式加工方法相比，低温钻孔可用于加工AZ31镁基复合泡沫，以获得良好的表面质量和完整性。
