Study on Rapidly Solidified Powder Magnesium Alloys

快速凝固粉末镁合金的研究

• 批准号: 01550539
• 负责人: KANEKO Junichi
• 金额: $ 1.6万
• 依托单位: Nihon University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01550539/
• 关键词: Magnesium Alloys; Rapid Solidification; Powder Metallurgy; Mechanical Properties; Age Hardening; Specific Strength; 比強度

Rapidly solidified P/M materials were produced for AZ91 and ZK61 magnesium alloys with alloying additions of Si, Ni, Mn and Ce, and their mechanical properties were examined, with the prupose of improving properties of conventionally processed magnesium materials. Rapidly solidified flakes showed cellular dendritic structures of 1 to 2 mum in the average cell size. The cooling rate during solidification was estimated as 10^4 to 10^5 K/s. P/M materials of 7 mm in diameter were produced by cold pressing and hot extrusion.Among obtained P/M materials of AZ91 based alloys, Si bearing alloy showed the highest peak hardness when aged at 433 K. Ni and Ce bearing alloys showed very little age hardening for both AZ91 and ZK61 based alloys. Mn bearing ZK61 alloy showed higher age hardening at 403 K than the base alloy. Rapid solidification of magnesium alloys with some proper alloying additions was shown to be very effective in increasing strength of magnesium alloys. Among the all tested materials, P/M materials of Ce added ZK61 alloy showed the highest tensile strength of 554 MPa. The specific strength of this alloy was as high as 295 MPa and exceeded those of 7075 aluminum alloy and Ti-6Al-4V. At elevated temperatures, rapidly solidified P/M materials showed lower tensile strength and higher elongation than I/M magnesium materials. P/M materials of AZ91 alloy showed elongation higher than 400% at 573 K, which is in the superplastic deformation regime. Thus, the salient features of rapidly solidified magnesium P/M materials are higher strength at room tempearture and higher ductility at elevated temperatures than the conventionally processed magnesium materials.

通过添加Si、Ni、Mn、Ce等合金元素，制备了AZ91和ZK61镁合金的快速凝固粉末冶金材料，并对其力学性能进行了测试，以期改善常规工艺的镁合金材料的性能。快速凝固的薄片显示平均细胞大小为1-2微米的细胞树枝状结构。通过冷压和热挤压的方法制备了直径为7 mm的粉末冶金材料。在获得的AZ91基合金粉末冶金材料中，硅轴承合金在433K时效时具有最高的峰值硬度，Ni和Ce轴承合金对AZ91和ZK61基合金的时效硬化很小。含锰ZK61合金在403K时的时效硬化明显高于基合金。在镁合金中加入适量的合金元素进行快速凝固，对提高镁合金的强度是非常有效的。在所有受试材料中，添加Ce的ZK61合金粉末冶金材料的抗拉强度最高，达到554 Mpa。该合金的比强度高达295 Mpa，超过了7075铝合金和Ti-6Al-4V合金。在高温下，快速凝固粉末冶金材料的抗拉强度低于I/M镁材料，而延伸率高于I/M镁材料。AZ91合金粉末冶金材料在573K时的延伸率大于400%，处于超塑性变形状态。因此，快速凝固镁粉末冶金材料的显著特点是常温强度高，高温塑性高。