晶界状态对定向凝固Al—Cu和Renel25合金热裂倾向的影响

Effect of Grain Boundary''''s State on the Hot Cracking Tendency of Directionally Solidified Al-Cu and Rene 125 Alloys

摘要:

在ＨＲＳ定向凝固设备上进行了合金热裂试验，采用半定量方法评定了定向凝固Ａｌ－Ｃｕ和Ｒｅｎｅｌ２５合金热裂倾向。观察了合金的晶界，并分析讨论了其对合金热裂的影响。用晶界状态分析的结果与试验结果完全一致。证明了晶界状态对热裂纹的形成有重要影响，其影响包括对晶间结合力的破坏作用和对晶界凝固收缩的补偿作用。晶界状态对热裂影响的综合作用取决于晶界低熔点相的分布和数量。

Abstract:

The experiments of the hot cracking tendency of the alloys were carried out in the HRS directionally solidified device. Hot cracking tendency of directionally solidified Al Cu and Rene 125 alloys was evaluated with a semi quantitative method. Grain boundaries were observed. Its effect on hot cracking is analyzed and discussed. The analysis result with grain boundary's state is in accordance with experiment result. It is proved that grain boundary's state has important influence on the formation of hot cracks. The effects include weakening the binding energy between grains and compensating solidification shrinking in grain boundaries. The comprehensive influence of grain boundary state on hot cracking tendency of an alloy depends on the distribution and amount of the phases with low melting points in grain boundaries.