表面加工工艺对钨-钠相容性特征的影响
Effect of the Surface Technical Procedure on the Compatibility Characters of W-Na
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摘要: 试验研究了表面加工工艺不同的旋锻钨和抛光钨与钠的相容性。在600℃、含30μg/g氧的金属钠中,旋锻钨和抛光钨的失重速率分别为1×10-4mm·a-1和2×10-4mm·a-1,两种钨与钠均有良好的相容性。旋锻钨试样在钠中的腐蚀失重量随着腐蚀时间增长而减少;抛光钨试样的失重量与腐蚀时间的倒数呈线性关系。X射线衍射分析显示,腐蚀后的旋锻钨试样表面腐蚀产物为NaxWOy和WxOy,而抛光钨则仅有NaxWOy。腐蚀失重曲线的不同和腐蚀产物的差异表明,表面加工工艺造成的表面状态对钨在钠中的腐蚀特性和机理有显著影响。经高温钠腐蚀后,旋锻钨试样的晶粒长大,断裂应力和显微硬度显著降低;高温钠腐蚀对抛光钨试样的断裂应力和显微硬度似乎无明显影响。断口分析结果显示,钠腐蚀前,旋锻钨和抛光钨试样的断口形貌均呈现沿晶脆断特征;钠腐蚀后,两种钨试样的沿晶脆断特征变得更为显著,为沿晶和穿晶混合型脆性断裂。Abstract: The compatibility of the tungsten with sodium were investigated. The weight loss rate in 600 ℃ sodium containing 30 μg/g oxygen is about 1×10~(-4) mm·a~(-1) and (2×10~(-4)) mm·a~(-1), respectively for the rotary swaging tungsten and polishing tungsten. The weight loss curves and the corrosion products of two kinds of W-specimens in high temperature sodium are difference significantly, and it indicates that the original surface conditions of the tungsten resulted from the surface technical procedures affect significantly the characters and mechanism of W-Na compatibility. The grain grow, the fracture stress and the micro-hardness are decreased significantly for the corroded rotary swaging W-specimen, and are not influenced so much for the polishing W-specimen. The micro-morphology of the fracture surface appears to be the inter-granular brittle before sodium corrosion for the rotary swaging and polishing W-specimens. The brittle morphologies become much more notable, and appear the inter-and trans-granular fracture mode after sodium corrosion at high temperature for both of W-specimens.