SPS制备多级孔结构钨骨架压缩性能及致密化行为研究  

Research on the Densification Behavior and Compression Performance of SPS Prepared Tungsten Skeleton with Hierarchical Pores Structure

作　　者：杨鑫[1] 王犇 谷文萍[2] 刘刚[1] 梁淑华[1] 武涛[1] 刘世锋[3] Yang Xin;Wang Ben;Gu Wenping;Liu Gang;Liang Shuhua;Wu Tao;Liu Shifeng(Shaanxi Key Laboratory of Electrical Materials and Infiltration Technology,Xi'an University of Technology,Xi'an 710048,China;School of Electronics and Control Engineering,Chang'an University,Xi'an 710061,China;School of Metallurgical and Engineering,Xi'an University of Architecture&Technology,Xi'an 710055,China)

机构地区：[1]西安理工大学陕西省电工材料与熔(浸)渗技术重点实验室,陕西西安710048 [2]长安大学电子与控制工程学院,陕西西安710061 [3]西安建筑科技大学冶金工程学院,陕西西安710055

出　　处：《稀有金属材料与工程》2021年第8期2913-2920,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51504191);陕西省自然科学基础研究(2020JM-455)。

摘　　要：以粒径分布为15~106μm多孔球形团聚W粉为原料,采用放电等离子体烧结(SPS)在不同烧结温度(1450、1500、1550℃),轴向恒压40 MPa,保温5 min下分别制备出高强度(347.8±10.6 MPa、407.4±14.2 MPa、543.9±8.7 MPa)、多级孔结构(3~10μm/200~500 nm)W骨架。结合XRD、SEM、万能试验机等检测技术,对SPS烧结过程中粉末致密化行为、显微组织变化及力学性能进行了系统研究。结果表明:SPS可制得烧结前后物相无明显变化、孔隙率介于30%~40%、烧结颈发育完全多级孔结构钨骨架。该多级孔W骨架SPS烧结致密化过程可分为4个阶段,第1阶段为升压阶段,烧结试样相对密度随压力升高而迅速升高;第2阶段为典型的颗粒重排阶段;第3阶段烧结温度高于1000℃,烧结试样相对密度随温度的升高而增加,属于典型的烧结中期;第4阶段为烧结末期,烧结体内部高温蠕变引起致密化程度进一步提高。利用高温蠕变模型研究了该多孔球形W粉的致密化机理为纯扩散致密化,通过颈长方程确定该多孔球形钨粉在整个SPS烧结过程中的致密化机理是以体积扩散为主,晶界扩散为辅。W skeleton with high strength(347.8±10.6 MPa,407.4±14.2 MPa,543.9±8.7 MPa)and hierarchical pores structure(3~10μm/200~500 nm)was prepared by sparking plasma sintering(SPS)at different sintering temperatures(1450,1500,1550℃)and at axial constant pressure(40 MPa)for 5 min using porous spherical agglomerate W powder with the particle size distribution of 15~106μm as raw material.The densification behavior,microstructure changes and mechanical properties of W in SPS process were systematically studied by XRD,SEM and universal testing machine.The results show that SPS can produce W skeleton which have developed sintered neck and hierarchical pores structure with no significant change in phase before and after sintering and porosity of 30%~40%.The sintering densification process of W skeleton with hierarchical pores structure by SPS can be divided into four stages:the first stage is the pressure increase stage in which the relative density of sintered sample increases rapidly with the increase of pressure;the second stage is a typical particle rearrangement stage;the third stage is a typical sintering metaphase in which the relative density of sintered sample increases with the increase of temperature,when temperature is higher than 1000℃;the fourth stage is the end of sintering,and the densification degree is further improved due to high temperature creep inside the sintered body.The densification mechanism of the porous spherical W powder is determined as pure diffusion densification by the high temperature creep model.Furthermore,the densification mechanism is determined to be volume diffusion as the main mechanism and grain boundary diffusion as the auxiliary mechanism by the neck length equation.

关 键 词：钨铜复合材料 钨骨架 SPS 多级孔结构 致密化行为 

分 类 号：TG146.411[一般工业技术—材料科学与工程]