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Production of Nonequilibrium Alloy Powders by Ultrasonic and High-Pressure Gas Atomization Method and their Properties

超声高压气体雾化法制备非平衡合金粉末及其性能

基本信息

批准号：
61490003
负责人：
INOUE Akihisa
金额：
$ 3.65万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

A new liquid quenching equipment by utilizing an ultrasonic and high-pressure gas atomization method was designed and constructed with the aim of developing a method which can produce effectively amorphous spherical powders. Many factors of producing amorphous powders in Fe- and Co-based alloy systems were investigated and the atomization condition of producing the amorphous powders was established. Subsequently, the consolidation of the amorphous powders was tried by press-sintering at elevated temperatures. As a result, it was clarified that the consolidation is difficult for the spherical powders and the mixing of flaky powders to the spherical powders is very effective for the formation of amorphous bulks. From this information, the atomization equipment was modified so as to produce flaky powders as well as spherical powders. In the modification, the rotator was set up at the position just below the gas atomization nozzle and small atomized liquid droplets were flattened by the rotator, resulting in the formation of flaky powders with a small thickness of 1 to 3 m. Furthermore, the heat of relaxation was much larger than that for the melt-spun ribbons, indicating the achievement of much higher cooling velocities by the two-stage quenching method. The increase of cooling velocity is probably due to the subsequent cooling of super-cooled liquid droplets produced by gas atomization. In addition, the two-stage quenching technique was found to bring about the glass formation in new alloy systems such as Fe-C binary alloys and a remarkable extension of glass formation range in glass-forming alloy systems. These features of the newly developed two-stage quenching technique consisting of ultrasonic and high-pressure gas atomization followed by impact flattening of the supercooled liquid droplets are concluded to be attractive enough to confirm further progress of the two-stage quenching technique and the resulting nonequilibrium alloy powders.

为了开发一种高效制备非晶球形粉末的方法，设计并建造了一种利用超声波和高压气体雾化方法的新型液体淬火设备。研究了在铁基和钴基合金体系中制备非晶态粉末的多种因素，确定了制备非晶态粉末的雾化条件。随后，采用高温压制烧结的方法对非晶粉末进行固结。结果表明，球形粉末不易固结，片状粉末与球形粉末的混合是形成无定形块体的有效途径。根据这一信息，对雾化设备进行了改进，以生产片状和球形粉末。在改进方案中，旋转器设置在气体雾化喷嘴的正下方，通过旋转器使细小的雾化液滴变平，形成厚度为1~3m的片状粉末，而且松弛热比快淬带的松弛热大得多，表明两级淬火方法实现了更高的冷却速度。冷却速度的提高可能是由于气体雾化产生的过冷液滴随后冷却所致。此外，在Fe-C二元合金等新合金系统中，采用两段淬火技术可以实现玻璃的形成，在玻璃形成合金系统中，玻璃的形成范围得到了显著的扩展。新开发的两段淬火技术包括超声和高压气体雾化，然后冲击压平过冷液滴，这些特点足以证明两段淬火技术和所产生的非平衡合金粉末的进一步发展。