氧化钇稳定立方晶型氧化锆增强钨基合金制备工艺及性能

Preparation process and properties of yttria stabilized cubic zirconia reinforced tungsten based alloys

采用共沸蒸馏法结合粉末冶金法制备了氧化钇稳定立方晶型氧化锆增强钨基合金（W-3.0 mass%YSCZ）。利用XRD、SEM、EDS、TEM等检测手段对合金制备过程中不同阶段材料组织、形貌及微观结构进行了分析与表征,测定了复合钨粉的粒度、钨合金的密度、显微硬度、磨损性能及动态压缩性能。结果表明：p H值对前驱体粉体的粒度有显著影响,p H=2的初始溶液制得的前驱体粉体粒径细小,随着初始溶液的p H值增大,复合粉末粒径逐渐增加;p H=2的初始溶液制得的前驱体粉经550℃×4 h煅烧后得到粒径为40～60 nm煅烧粉体,再经750℃×2 h＋900℃×4 h氢气还原后得到尺寸为35～50 nm的钨与ZrO_2-Y2O3构成的近球形纳米级复合粉末;制得的钨合金中的ZrO_2为立方晶型,表明常温下Y2O3对ZrO_2晶型起到了稳定作用;ZrO_2-Y_2O_3颗粒对钨晶粒具有明显的细化作用,获得的钨晶粒粒径为3～6μm;钨基合金相对密度达90.9%,抗压强度达到1009 MPa,耐磨性较纯钨提高了约18.7%。

Yttria stabilized cubic zirconia reinforced tungsten based alloys（ W-3. 0 mass% YSCZ） was developed via azeotropic distillation method and powder metallurgy method. The morphology,phase and microstructure of the materials during the preparation of the tungsten based composite material were analyzed and characterized by means of SEM,TEM,XRD,and EDS analysis,the particle size of the powders,density,micro-hardness,abrasive resistance and dynamic compression performance of the tungsten alloy were measured. The results show that the initial p H value of the solution affects the morphology and size of the doped tungsten powders. The particle size of the precursor powder prepared using the solution with p H = 2 is small,with the increase of the initial p H value of the solution,the composite powder particle size increases gradually. After calcination at 550 ℃ for 4 h,the size of the composite powders prepared from the initial solution of p H = 2 is 40 to 60 nm. After hydrogen reduction at 750 ℃ for 2 h and then at 900 ℃ for 4 h,the composite powder presents a near sphere structure consisted of W and ZrO_2-Y_2O_3 with a narrow size distribution of 35 to 50 nm. The ZrO_2 in the tungsten alloy is cubic crystal,which shows that Y2O3 has a stable effect on ZrO_2 crystal at room temperature. ZrO_2-Y2O3 particle can refine the grain of the tungsten alloy and the size of the tungsten alloy grain is 3-6 μm. The relative density is 90. 9%,the compressive strength reaches1009 MPa and abrasion resistance improves approximately 18. 7% of the tungsten alloy compared with that of pure tungsten.