CNTs和Ti掺杂对W基合金微观组织结构及力学性能的影响  

Influence of CNTs and Ti on the Microstructure and Mechanical Properties of W-Based Alloys

作　　者：张玉翠[1] 沙建军[1] 王永昌[1] 王首豪 杨晓丽[1] 

机构地区：[1]大连理工大学工业装备结构分析国家重点实验室,辽宁大连116024

出　　处：《稀有金属材料与工程》2017年第3期835-840,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50871092;91216201);中央高校基本科研业务费专项基金(DUT11ZD(G)01)

摘　　要：采用高能球磨与热压烧结工艺,在1500℃、25 MPa压力下制备了CNTs和Ti掺杂的W基合金。利用三点弯曲法和单边缺口梁法(SENB)分别对合金的弯曲强度和断裂韧性进行了测试。使用扫描电镜(SEM)和能谱(EDS)分析仪对合金的微观组织形貌进行了观察与分析。结果表明:单独掺杂CNTs和Ti都可以改善W合金的烧结性能,制备的W-0.1CNTs和W-5Ti合金的致密度显著提高,但晶粒尺寸较大。而同时掺杂CNTs和Ti不仅可以改善W合金的烧结性能,而且可以明显抑制W晶粒长大;CNTs含量对W合金力学性能有明显的影响,对于W-5Ti-0.1CNTs合金,力学性能最好,其硬度、抗弯曲强度和断裂韧性分别为7.32 GPa、654.3 MPa、10.13 MPa·m1/2;断口微观组织形貌分析表明,单纯加入CNTs或Ti,断裂方式是以沿晶断裂为主,Ti的加入,在W晶粒的三重晶界处形成Ti(W)固溶体;而同时加入CNTs和Ti所制备的W合金,晶粒明显被细化,断裂方式由沿晶断裂转变为沿晶断裂和穿晶解理断裂的混合模式,CNTs和Ti的同时加入对W基材料起到了很好的增强增韧效果。W-based alloys were fabricated at 1500 °C under a pressure of 25 MPa by high-energy ball milling and hot pressing, using the CNTs and Ti as the dopants. The influence of different dopants on the sintering density, morphologies and mechanical properties of sintered W-based materials was investigated. The microstructure was characteri zed by scanning electron microscopy（SEM） with energy dispersive spectrometer（EDS）. The fracture strength and toughness were measured by three-point bending and single edge-notched beams tests, respectively. Results indicate that both CNTs and Ti can effectively enhance the sintering behavior. The W-0.1CNTs and W-5Ti exhibit a high relative density of 95.8% and 96.5%, respectively, but their grain size is large. In case of W-5Ti-0.1CNTs alloy, the density is high and the addition of CNTs and Ti can retain the grain size. W-5Ti-0.1CNTs alloy shows the excellent mechanical properties. The microhardness, fracture strength and fracture toughness of W-5Ti-0.1CNTs alloy are 7.32 GPa, 654.3 MPa, 10.13 MPa·m1/2, respectively. The intergranular fracture is the main mode for the W-0.1CNTs and W-5Ti alloys, but the W-5Ti-0.1CNTs fractures in a mixture mode of intergranular and transgranular fracture. These results demonstrate that co-addition of CNTs and Ti can refine the microstructure and enhance the strength and fracture toughness of W-based alloys.

关 键 词：W W基合金 碳纳米管 高能球磨 热压烧结 

分 类 号：TG146.411[一般工业技术—材料科学与工程]