K403合金铸造涡轮叶片热裂的研究

研究表明，热裂是合金枝晶间液体处于不连通状态的温度与合金完全凝固温度范围内产生，铸造涡轮叶片热裂最常出现的部位是叶冠与叶身或者榫根与叶身的连接段，热裂在外貌上呈弯曲不规则形状，通常是不连续的，常有几条裂纹沿枝晶间或晶界向相同的方向扩展，热裂严重区断口呈光滑的“土豆”状，在热裂扩展出现光滑区与撕裂并存。降低合金初熔温度的微量合金化元素（如Ｂ，Ｚｒ）明显增加了热裂的敏感性。

Investigation on Hot Cracking of Cast K403 Superalloy Turbine Blades

Hot cracking takes place in a temperature range during solidification of alloys,in which the liquid of interdendrites does not interconnect and the solidification of alloys is completed The hot cracks of cast turbine blades often appear at the connecting positions between top of blades and airfoil or between root of blades and airfoil The morphology of hot cracks is zigzag,irregular and discontinuous The several cracks normally propogate along interdendrites or grain boundaries at the same direction The fracture surface in the serious hot cracking zone seems to be smooth potato like shape and the coexistence of the smooth zone and the tearing region appears in the propagating zone of hot cracking The minor alloying elements which decrease the incipient melting temperature of alloys,such as B and Zr,enhance sensibility of hot cracking obviously