Microstructure and thermal stability of sintered pure tungsten processed by multiple direction compression  

多向压缩纯钨烧结体的组织及热稳定性（英文）

作　　者：Ping LI Da-zhi SUN Xue WANG Ke-min XUE Rui HUA Yu-cheng WU 李萍;孙大智;王雪;薛克敏;华睿;吴玉程

机构地区：[1]合肥工业大学材料科学与工程学院,合肥230009

出　　处：《Transactions of Nonferrous Metals Society of China》2018年第3期461-468,共8页中国有色金属学报（英文版）

基　　金：Project(51675154)supported by the National Natural Science Foundation of China;Project(2014GB121000)supported by the National Magnetic Confinement Fusion Program,China

摘　　要：Multiple direction compression(MDC)was conducted on sintered pure tungsten(99.9%,mass fraction)with different reductions at 1423 K.The microstructure,microhardness and thermal stability of the MDC-processed samples were studied by X-ray diffraction(XRD),electron backscattered diffraction(EBSD)and differential scanning calorimetry(DSC)compared with those of the initial sintered tungsten.The results show that the dislocation density increases significantly with the reduction of MDC,ranging from 3.08×1014 m-2 for the initial sintered tungsten to 8.08×1014 m-2 for the tungsten after MDC with the reduction of 50%.The average grain size decreases from 83.8 to 14.7μm and the microhardness value increases from HV0.2 417 to HV0.2 521.The recrystallization temperature for the tungsten samples processed by MDC is approximately constant at around 1600 K.The MDC of sintered tungsten results in a decrease of grain size concurrent with an increase of uniformly distributed nucleation sites,which leads to the improvement of the thermal stability.对纯度为99.9%的纯钨烧结体在1423 K进行不同压下量的多向压缩(MDC)实验,采用X射线衍射(XRD)、电子背散射衍射(EBSD)及差示扫描量热法(DSC)研究多向压缩前后纯钨试样组织、显微硬度及热稳定性的变化。结果表明,多向压缩后纯钨烧结体位错密度显著增大,压下量50%纯钨试样的位错密度由初始烧结钨的3.08×10^(14)增大至8.08×10^(14) m^(-2),平均晶粒尺寸由83.8μm细化至14.7μm,而显微硬度则由HV0.2 417增大至HV0.2 521。多向压缩后纯钨试样的再结晶温度约为1600 K,近似为常数。纯钨烧结体经多向压缩后由于晶粒尺寸减小以及均匀分布的形核点增多,组织热稳定性得到提高。

关 键 词：multiple direction compression(MDC) sintered tungsten dislocation density mechanical properties thermal stability 

分 类 号：TF125.241[冶金工程—粉末冶金]