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本文研究包晶反应结晶过程中产生的的热裂纹。将MTS抗拉实验机与反射炉相结合进行了一系列的现场结晶实验。在结晶过程中测量试样温度和应力变化。应力测量在试样的结晶过程中突然下降(发生在合金的包晶温度左右),一般都会产生微组织中的裂纹或者回填裂纹。而且从理论和实验上对包晶反应类型进行了研究,理解其对结晶过程应力变化的影响。理论分析显示,由于包晶转变引起的应力改变是热裂纹形成的原因之一。此外,当合金初次析出充分,包晶反应不散射时,裂纹就更容易产生。
This paper studies the peritectic reaction during the crystallization of hot cracks. A series of field crystallization experiments were carried out by combining MTS tensile testing machine with reverberatory furnace. The sample temperature and stress changes were measured during crystallization. Stress measurement suddenly drops during the crystallization of the sample (occurring at the peritectic temperature of the alloy) and typically produces cracks or backfill cracks in the microstructure. In addition, the type of peritectic reaction has been studied both theoretically and experimentally to understand its effect on the stress change in the crystallization process. Theoretical analysis shows that the change of stress due to peritectic transformation is one of the reasons for the formation of hot cracks. In addition, when the alloy is precipitated for the first time, the peritectic reaction does not scatter, the crack is more likely to occur.