摘要
在原材料粉末中添加20μm的粗颗粒钨粉,用粉末冶金法制备了圆柱状90W-Ni-Fe钨合金。通过测量钨合金烧结坯椭圆状横截面长短轴的尺寸,对烧结变形进行了定量分析;采用准静态拉伸试验对合金的力学性能进行了测试;通过光学金相、扫描电镜对合金组织形貌进行表征。结果表明：添加粗颗粒W粉能明显降低合金烧结变形,粗颗粒钨粉添加量占钨粉总量80%时,圆柱状钨合金投料可降低约20%,明显提高材料利用率;当粗颗粒W粉含量在70%~90%之间时,合金抗拉强度约950 MPa,延伸率约20%,与未添加粗颗粒钨粉的传统90W-Ni-Fe钨合金相比,其强度提高约30MPa,延伸率降低了28.5%,这与添加粗颗粒W粉的钨合金的穿晶断裂方式,以及合金界面结合强度低、黏结相分布不均匀等有关;添加粗颗粒钨粉的钨合金微观组织中的钨晶粒形状不太规则,存在粒径超大的钨晶粒。
Cylindrical 90W-Ni-Fe tungsten heavy alloys were prepared by means of powder metallurgy with the addition of 20μm coarse tungsten powder. Sintering warpage was investigated through measuring and computing the major to minor axis ratio of oval intersecting surface. The tensile strength and elongation of alloys were tested with quasi-static tensile testing machine. Optical microscope（ OM） and scanning electricity microscope（ SEM） were used to characterize microstructure of alloys,respectively. The results indicate that sintering warpage significantly decreases with coarse tungsten powder additions,and the material charge amount can reduce to about 80% when producing cylindrical tungsten heavy alloys,the utilization ratio of materials increase obviously; When coarse tungsten powder addition is in the range of 70 ~ 90%,the tensile strength is about 950 MPa and and elongation is about 20%,respectively,compared with the alloys without coarse tungsten powder,the tensile strength increase by 30 MPa and the elongation reduces by 28. 5%. The results are caused by transgranular fracture,low interface combination strength and non-uniform distribution of binding phase,etc; The tungsten crystal grains are irregularity with existence of the super large tungsten crystal grains.
出处
《粉末冶金技术》
CAS
CSCD
北大核心
2016年第3期199-204,共6页
Powder Metallurgy Technology
关键词
90W-Ni-Fe钨合金
粗颗粒
烧结变形
力学性能
晶粒
coarse tungsten powder
tungsten heavy alloy
sintering warpage
mechanical properties
crystal grain
