ABSTRACT

The processes of forging without canning were optimized, such that forging could be successfully performed and forged pancakes without cracks could be obtained. The maximum height reduction could reach 80%. The as-forged microstructure consisted of γ and β/B2 phases. The volume fraction of the β/B2 phase rose slightly compared to the pre-forging state. Near the top or bottom of the pancake, residual lamellae were found, while full dynamic recrystallization was completed at the center and lateral parts. Equiaxed γ grains illustrated that dynamic recrystallization mainly occurred in the γ phase, while the softer β phase coordinated the deformation by adjusting morphology. Two types of Σ3 boundaries, [110] 70° and [111] 60°, were found in the γ phase. At room temperature, the fracture was brittle, and the elongation was 0.07%. With increasing temperature, the yield strength and ultimate strength decreased, while the elongation increased. The brittle–ductile transition temperature was between 800°C and 850°C.

摘要

优化无罐头锻造工艺，使锻造成功，获得无裂纹的锻造薄饼。最大高度降低可达80%。锻造时的显微组织由 γ 和 β/B2 相组成。与锻造前状态相比，β/B2 相的体积分数略有上升。在薄饼的顶部或底部附近，发现残留的薄片，而在中心和侧面部分完成了充分的动态再结晶。等轴γ晶粒说明动态再结晶主要发生在γ相，而较软的β相通过调整形貌来协调变形。在γ相中发现了两种类型的Σ3边界，[110] 70°和[111] 60°。常温下断裂脆性，伸长率为0.07%。随着温度升高，屈服强度和极限强度降低，而伸长率增加。脆-韧转变温度在 800°C 和 850°C 之间。