激光功率对高熵黏结相高密度钨合金组织和性能的影响  

Effect of Laser Power on the Microstructure and Properties of High-density Tungsten Alloy with High-entropy Binder Phase

作　　者：袁媛[1] 韩勇[1] YUAN Yuan;HAN Yong(Powder Metallurgy Research Institute,Central South University,Changsha 410083,Hunan,China)

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083

出　　处：《中国钨业》2024年第6期41-49,57,共10页China Tungsten Industry

基　　金：国家自然科学基金(52371041)。

摘　　要：激光增材制造能实现钨合金复杂结构一体化成形,成为当前研究的热点方向。激光工艺参数对增材制造钨合金的组织和性能具有重要影响,因此本文利用激光定向能量沉积(L-DED)方法制备了高熵黏结相高密度W-NiFeCoNbAlV(W含量为85%)钨合金,探索了激光功率对85W合金组织和性能的影响。发现L-DED成形的85W合金皆由球形W颗粒、树枝状W相和Ni基黏结相组成,黏结相中皆呈现典型的胞状结构且富Nb元素。随着激光功率增加,析出的树枝状W相增多,呈现球状W颗粒和树枝状W相交替的组织,且抗拉强度和压缩屈服强度皆得到提高。当激光功率增加到最大为1600 W时,85W合金的抗拉强度和压缩屈服强度皆最高,分别为1180 MPa和1120 MPa。该合金独特的胞状结构和析出W相有效阻碍位错运动,从而实现位错钉扎,进而强化合金性能。Laser additive manufacturing,enabling the integrated fabrication of complex tungsten alloy components,has emerged as a pivotal research focus.Given the critical influence of laser process parameters on the microstructure and properties of additively manufactured tungsten alloys,this study employed laser-directed energy deposition(L-DED)to fabricate a high-density 85W-NiFeCoNbAlV alloy(85%W)with a high-entropy binder phase,systematically investigating the effects of laser power on its microstructure and mechanical performance.Results reveal that the L-DED-processed 85W alloy consists of spherical W particles,dendritic W phases,and a Ni-based binder phase.The binder phase exhibits cellular structures with pronounced Nb enrichment.Increasing laser power promotes the precipitation of dendritic W phases,forming alternating microstructures of spherical W particles and dendritic W phases.Consequently,both tensile strength and compressive yield strength improve significantly.At the maximum laser power of 1600 W,the alloy achieves optimal mechanical properties,with tensile strength and compressive yield strength reaching 1180 MPa and 1120 MPa,respectively.This performance enhancement is attributed to the unique cellular structures and precipitated W phases,which effectively hinder dislocation motion through dislocation pinning mechanisms.

关 键 词：激光定向能量沉积 激光功率 高熵黏结相 抗拉强度 压缩屈服强度 

分 类 号：TG146.411[一般工业技术—材料科学与工程]