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Application of Mechanically Alloyed Al-Ti-B P/M Materials to Grain Refining of Aluminum Castings

机械合金化Al-Ti-B粉末冶金材料在铝铸件晶粒细化中的应用

基本信息

批准号：
62850127
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 Developmental Scientific Research
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-62850127/
关键词：
Grain refinement Casting structure Aluminum castings Al-Ti alloy Al-Ti-B alloy Powder metallurgy Mechanical alloying AlーTiーB合金分散強化材

项目摘要

P/M materials of Al-Ti and Al-Ti-B alloys, which were processed from mechanically alloyed powders by cold pressing and hot extrusion, were used as grain refiner for aluminum castings. In Al-Ti-B alloys, constituent phase of Ti was varied as metallic Ti, TiAl_3 and TiB_2, and that of B as metallic B, TiB_2 and AlB_2, in order to discuss the mechanisms of grain refining in aluminum castings by the addition of Ti and B. Grain refiner was added to 99.9% aluminum melt,and cast into both metal mold and thermally insulated mold. The macro structures of the ingots were examined and the extent of grain refinement was evaluated.When mechanically alloyed powder was directly added as grain refiner, attained grain refining was not as much as in case of addition of P/M material of the same composition, due to oxidation loss occurred in the former. The P/M Al-TiAl_3 alloy is more effective as the grain refiner than conventional Al-Ti mother alloy, due to finer TiAl_3 dispersion in P/M material. The P/M Al-Ti-B materials containing TiB_2 are less effective, and thus, TiB_2 is not an effective nucleant for aluminum. P/M materials containing TiAl_3 and AlB_2 are most effective under the condition of short time and lower temperature holding of the melt after addition of grain refiner. However, those containing metallic Ti and B are as effective as conventional Al-Ti-B alloy hardners. P/M materials with fine dispersion of TiB_2 or TiC showed higher strength at high temperatures than commercial aluminum alloys. Both TiAl_3 and TiAl were found to become amorphous aer mechanical alloying, but they became crystalized after heating for hot extrusion.

Al-Ti和Al-Ti-B合金粉末冶金材料是由机械合金化粉末经冷压和热挤压加工而成，用作铝铸件的晶粒细化剂。在Al-Ti-B合金中，将Ti的组成相改为金属Ti、TiAl_3和TiB_2，将B的组成相改为金属B、TiB_2和AlB_2，以探讨添加Ti和B细化铝铸件晶粒的机理。在99.9%铝熔体中添加晶粒细化剂，分别浇注到金属型和保温型中。研究了铸锭的宏观组织并评价了晶粒细化的程度。当直接添加机械合金化粉末作为晶粒细化剂时，由于前者发生了氧化损失，所达到的晶粒细化程度不如添加相同成分的粉末冶金材料。 P/M Al-TiAl_3 合金作为晶粒细化剂比传统的 Al-Ti 母合金更有效，因为 TiAl_3 在 P/M 材料中的分散更细。含有TiB_2的P/M Al-Ti-B材料效果较差，因此TiB_2不是铝的有效成核剂。含有TiAl_3和AlB_2的粉末冶金材料在加入晶粒细化剂后熔体保温时间短、温度较低的条件下最为有效。然而，含有金属 Ti 和 B 的硬化剂与传统的 Al-Ti-B 合金硬化剂一样有效。细分散TiB_2或TiC的P/M材料在高温下表现出比商业铝合金更高的强度。 TiAl_3和TiAl都成为非晶态空气机械合金化，但在热挤压加热后变成晶态。