论文部分内容阅读
采用拉伸试验机研究了固溶强化Ni-20Cr-18W基热变形高温合金锻造后的室温拉伸行为,用光学显微镜(OM)和扫描电子显微镜(SEM)分析了锻造前后的微观组织及拉伸断口形貌。利用X射线衍射(XRD)确定了合金中碳化物的类型。结果表明,合金铸态组织为典型的枝晶结构;锻态组织晶粒尺寸为60~70μm,晶粒度为ASTM 5级,M6C型碳化物半连续分布在晶界上。M6C型碳化物钉扎晶界,提高了合金的强度;拉伸变形使晶界上的M6C型碳化物进一步破碎,造成外载荷分布均匀性下降,影响合金的塑性。合金的室温拉伸断口为韧性等轴韧窝断裂。
The tensile testing machine was used to study the tensile behavior at room temperature of the as-cast Ni-20Cr-18W superalloy after forging. The microstructure of the as-cast Ni-20Cr-18W superalloy was analyzed by optical microscope (OM) and scanning electron microscopy (SEM) Broken mouth shape. The types of carbides in the alloy were determined by X-ray diffraction (XRD). The results show that the as-cast alloy has a typical dendritic structure. The grain size of the as-cast microstructure is 60-70 μm, the grain size is ASTM 5, and the M6C carbides are semi-continuously distributed on the grain boundaries. M6C carbide pinning grain boundaries, improve the strength of the alloy; Tensile deformation of the grain boundary on the M6C carbide further broken, resulting in decreased uniformity of the external load distribution, affecting the plasticity of the alloy. The room temperature tensile fracture of the alloy is toughness equiaxed dimple fracture.