(1. 湖南大学 材料科学与工程学院，长沙 410082；
2. 湖南大学 汽车车身先进设计制造国家重点实验室，长沙 410082；
3. 国核宝钛锆业股份公司，宝鸡 721013)
摘 要: 采用扫描电镜(SEM)、电子背散射衍射(EBSD)、X射线衍射(XRD)、透射电镜(TEM)和万能试验机等，研究真空退火对新型Zr-Nb-O-Cu锆合金微观组织与力学性能的影响。结果表明：在580 ℃、3 h退火条件下，合金的平均晶粒尺寸为2.5 μm，晶粒为等轴晶，退火前后均存在{0001} 和{0001} 两种织构，但基面织构强度有所降低。第二相颗粒在晶内和晶界呈弥散分布，为体心立方(BCC)结构的β-Nb相与密排六方(HCP)结构的Zr-Nb-Fe相，尺寸集中在30~150 nm之间。相对于原材，退火后合金沿轧制方向(RD)和垂直方向(TD)的屈服强度(σs)及抗拉强度(σb)均下降，试样均韧性断裂。3个方向的应变硬化指数(n)与塑性应变比(r)差异明显。晶粒与第二相的尺寸、织构等因素对力学性能有重要影响。
关键字: 新型锆合金；织构；第二相；力学性能；退火
（1. College of Materials Science and Engineering, Hunan University, Changsha 410082, China;
2. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China;
3. State Nuclear Bao Ti Zirconium Industry Company, Baoji 721013, China）
Abstract:Scanning electron microscopy(SEM), electron backscatter diffractometry(EBSD), X-ray diffractometry(XRD), transmission electron microscopy(TEM) and universal testing machine were used to research the effects of vacuum annealing on the microstructure and mechanical properties of a novel Zr-Nb-O-Cu alloy. The results show that the grain is equiaxed possessing an average size of 2.5 μm and the strength of basal texture is reduced by being annealed at 580 ℃ for 3 h, {0001} and {0001} texture exist stably. The second phase particles (SPPs) are body-centered cubic (BCC) β-Nb phase and hexagonal close packed (HCP) Zr-Nb-Fe phase, it disperses inside the grain and along the grain boundary and its size is concentrated in 30-150 nm. Comparing to original material, the yield strength(σs) and tensile strength(σb) after annealing are decreased in rolling direction (RD) and transverse direction (TD), the fractured surfaces are ductile. There are significant differences in strain hardening index (n) and plastic strain ratio (r) in three directions. The factors including the size of grains and the SPPs, the transform of texture, have considerable effect on the mechanical properties.
Key words: novel zirconium alloy; texture; second phase; mechanical property; annealing
