摘要
采用声发射技术研究了5621S及添加1％Nd的5621S钛合金,在700℃、800℃、850℃空气中所形成的氧化膜于冷却过程中的开裂和剥落。重点分析了含Nd合金所形成的复合氧化物“钉子”对氧化膜的粘附性的影响,“钉子”的存在对于膜内裂纹的扩展起着延长距离及阻碍作用。实验表明,含钕合金氧化膜的粘附性虽得到极大改善,而膜仍易于开裂。这是因为在冷却过程中,“钉子”受到大的压应力。如果“钉子”较大,就会成为萌生裂纹的起始点。文中还分析了裂纹产生机制。
The spalling processes of the oxide scales formed on 5621S alloy(Ti-5Al-6Sn-2Zr-1Mo-0. 25Si)and 5621S alloy containing 1％Nd during cooling from 700℃, 800℃,850℃ were studied by using acoustic emission technique. The effect of composite oxide 'pegs' composed mainly of Nd_2O_3 on the adherence of oxide scales was analyzed. The 'pegs' can extend the distance between cracks and retard their movement in the oxide. The results indicate that the adherence of the oxide scale is improved due to the addition of Nd. However,the oxide scale still cracks easily. This is because that the 'pegs' suffer high compressive stress during cooling of specimen. If the 'pegs' are large enough, some of them can serve as centers of crack initiation. The mechanism of crack formation caused by the 'pegs' is also discussed.
出处
《中国腐蚀与防护学报》
CAS
CSCD
1991年第3期217-224,共8页
Journal of Chinese Society For Corrosion and Protection
基金
国家自然科学基金
