钨钼室温脆性的研究

对不同实验条件下制备的钨和钼的试样作扫描电镜、透射电镜和俄歇电子能谱分析。断口形貌分析表明,在室温下烧结态和再结晶态的断口呈典型的晶间脆性断裂,低形变及再结晶试样为晶间脆断和穿晶解理的混合型断裂,高度形变的试样断口呈纤维状韧性断裂特征,是纤维束撕裂、分层,而后单个纤维出现缩颈、微孔合并所致。在10~(-9)Torr高真空度下对新鲜断口作俄歇电子能谱分析证实,间隙杂质磷、氧和碳是钨的主要晶界杂质,而钾、氧和碳则在掺杂钨的晶界明显富集,可以确认这些在晶界大量富集的杂质是削弱晶界强度,造成钨钼室温脆性的基本原因.文中还分析了晶粒结构和亚结构对室温脆性的影响。

A STUDY ON THE BRITTLENESS OF W AND Mo AT ROOM TEMPERATURE

The specimens of W and Mo with bcc structure were analyzed by scanning electron microscope, transmission electron microscope and Auger electron energy spectrum. An analysis of fracture surface indicated that the brittle intercrystalline rupture was the main way in which the sintered and recrystallized W and Mo fail at room temperature, and that there was also a mixture of cleavage and intercrystalline rupture in the lower deformed specimens. Highly deformed samples showed the character of the fibred ductile fracture. Auger analysis of fracture surface proved that brittleness at room temperature resulted mainly from obvious gathering of interstitial impurities, P, O, N and C at grain boundaries. The present work also analyzed the influences of both the grain structure and the substructure on the brittleness of W and Mo at room temperature.