Research on the Hot Ductility of Fe-36Ni Invar Alloy

摘要:

通过Gleeble-3800热模拟实验机和微机控制万能材料试验机对Fe-36Ni因瓦合金的热塑性进行了研究。结果表明：在1050~1200 ℃，由于动态再结晶出现，合金展现出了良好的热塑性，这说明在热加工过程中，终轧温度不应低于1050 ℃。在800~1000 ℃时，Fe-36Ni因瓦合金热塑性较差，表现为脆性断裂，晶界滑移是其主要断裂机制。经氧化后，合金基体产生严重的内氧化，内氧化层由晶间氧化区和晶内氧化区组成。压缩试验表明，在变形过程中，晶间氧化会导致裂纹的产生，进而显著恶化合金的热塑性。

Abstract:

The hot ductility of Fe-36Ni invar alloy was studied by a Gleeble-3800 thermal-mechanical simulator and a microcomputer control universal material testing machine. The results show that the alloy has a good hot ductility (RA above 70%) at 1050~1200 °C, which illustrates that the alloy might be suitable for the rolling provided the finish rolling temperature does not go below 1050 °C. Dynamic recrystallization occurred and was found to be responsible for the better hot ductility. However, the alloy exhibits a hot ductility drop (RA below 50%) at 800~1000 °C, which is mainly attributed to the presence of the grain boundary sliding. Serious subscales, which had a typical substructure of the intragranular subscale and the intergranular subscale, occurred in the matrix after oxidation. The compression test indicates that the intergranular subscale will lead to the cracks and significantly deteriorate the hot ductility during deformation process.