熔体处理温度对K424高温合金凝固组织和性能的影响

Effect of Melt Treatment Temperature on Solidification Microstructure and Properties of K424 Superalloy

研究了不同熔体处理温度对K424镍基铸造高温合金凝固组织和力学性能的影响。结果表明,随着熔体处理温度的升高,MC型碳化物不断细化,分布更加弥散均匀,晶粒尺寸和二次枝晶间距减小,微观偏析得到改善;当熔体处理温度达到1 600℃以上时,合金的拉伸塑性和持久性能显著提高;但是熔体处理温度过高会加剧坩埚反应,导致1 650℃时氧含量明显增加,合金的拉伸强度和持久寿命出现下降趋势。

The influences of melt treatment temperature on the solidification microstructure and mechanical properties of K424 cast superalloy are studied. The results show that with the increase of melt treatment temperature, the carbide MC becomes finer and more homogeneous. Both the grain size and secondary dendrite arm spacing are decreased, and the micro segregation is also improved. When the melt treatment temperature is over 1 600 ℃, the tensile plasticity and the stress-rupture properties are improved evidently. But the crucible reaction is intensified when the melt treatment temperature is too high, which leads to the significant increase of oxygen content and decrease of tensile strength and rupture life at 1 650 ℃.