摘要
通过冷轧制备了变形量分别为10%和30%的Zr-2.5Nb合金试样,利用X射线衍射仪(XRD)、扫描电镜(SEM)、万能试验机、显微硬度计研究了在两相区内退火温度的改变对Zr-2.5Nb合金组织与性能的影响。结果表明:对于不同变形量的组织在相同的退火工艺下,变形量与初生α相的体积分数呈反相关,α相的晶粒尺寸在3~4μm之间波动。不同变形量冷轧的Zr-2.5Nb合金试样强度硬度随退火温度升高而升高,在750℃时强度值最高,然后随着温度的增大逐渐减小,当退火温度达到900℃硬度又有小幅增大。另外实验结果显示随着变形量的增大,试样的硬度增大,硬度值提升5%左右。在相同变形量下的试样随着退火温度的逐渐增加,材料的屈服强度和抗拉强度呈现出先增加后降低的变化趋势,而断后延伸率呈现先降低后升高的趋势,并在750℃时达到极限值。另外随着试样变形量的逐渐增大,材料的抗拉强度与屈服强度明显增加,而断后延伸率降低。未退火和退火状态下试样拉伸后得到的断口表面呈纤维状,表现出来的断裂特征都是韧窝,均属于韧性断裂。
In this paper,the effects of annealing in two-phase zone on the microstructure and properties of Zr-2.5Nb alloy under cold rolling with different deformation were studied.Differential scanning calorimetry(DSC)curve of Zr-2.5Nb alloy was determined by STA449C differential scanning calorimeter produced by Netzsch company in Germany.The plates were subjected to the hot-rolling and cold-rolling deformation pretreatment before annealing treatment,described as follows:the received plates were firstly hot-rolled deformed at 850℃with a reduction of 50%,followed by air cooling to room temperature;then,the hot-rolled plates were rolled out by 10%and 30%respectively at room temperature.Finally,these rolled plates were annealed at an intercritical temperature of 700,750,800,850 and 900℃for 1 h,followed by air cooling to room temperature.All treatments had been finished at KLG-12 Y vacuum resistance furnace.The phase composition of the duplex microstructure obtained at various temperatures was examined via X-ray diffraction(XRD)by Rigaku D/max-2500.After annealing,the samples were analyzed by S-4800 scanning electron microscope(SEM).The tensile and hardness properties of the annealed specimens were tested.The fracture surface morphologies of the failed specimens were examined using SEM to characterise the fracture mode of the alloy.All samples were cut along the rolling direction.Zr-Nb binary phase diagram showed that the starting and ending transformation temperature ofα→βwas 660 and 930℃.It could be seen that for unannealed sample and annealed samples at 700℃,two kinds of diffraction peaks representingαphase andβphase were detected.It could be seen that for unannealed sample and annealed samples at 750~850℃,three kinds of diffraction peaks representingαphase,βphase andωphase were detected.Diffraction peak ofωphase was strongest at 750℃annealing.The results showed that the content ofωphase was the highest at 750℃.When the annealing temperature was 900℃,ωphase disappeared,there were onlyαandβ.The
作者
王鑫
王旭彪
Wang Xin;Wang Xubiao(Mechanical and Electrical Engineering Department,Langfang Yanjing Vocational Technical College,Langfang 065200,China;State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qin⁃huangdao 066004,China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2021年第11期1309-1316,共8页
Chinese Journal of Rare Metals
基金
国家自然科学基金项目(51601165)资助
