液—固掺杂垂熔钨坯中改性元素的行为

对传统粉末冶金方法(液—固混合制成掺杂钨粉,经过压制、烧结、旋锻、拉拔等工序)制成的钨坯和钨丝,用扫描电子显微镜进行了断面及磨面分析。结果发现:在晶界孔穴内,元素Si和Al的含量丰富;在晶内孔穴内,除元素Si、Al外,还富集了元素K。只用钾泡理论解释改性元素改善高温钨丝的抗下垂性能是不够的,应以分子筛理论和SiO_2-Al_2O_3系统相图予以补充。

THE BEHAVIOR OF IMPROVED ELEMENTS IN SWAGING TUNGSTEN BILLET MIXED BY SOLID-LIQUID METHOD

The analysis of the fracture and milling surface of swaging tungsten billets and drawing tungsten wire was made by the scanning electronic microscope. These sample were done by traditional process: making powder doped by Liquid-Solid mixing method, pressing, sintering, swaging, drawing etc. Results indicate that elements of silicon and aluminium are richened in the cavity on grain boundary; except elements of silicon and aluminium, likewise, the element of potassium is also richened in the interior cavity in crystalline grain. The theory of potassium bubble can be used for explaining the creep characteristic under high temperature. Otherwise, the theory of molecular sieve and phase diagram of SiO_2-Al_2O_3 System may also be used for explaining compensation for high temperature properties of tungsten wire.