注射成形低钨-钨连接度的90W-6Ni-4Mn的高比重合金及其组织与性能研究

Microstructure and properties of 90W-6Ni-4Mn alloy with low W-W contiguity by metal injection molding

作为新一代动能穿甲弹材料,90W-Ni-Mn合金的制备一直存在W-W连接度高、烧结密度低以及加工成本过高等问题。为此,实验使用化学镀镍工艺对钨粉末进行处理,通过注射成形技术为喂料塑形,采用氩气-氩氢两步气氛烧结工艺制备出了低W-W连接度的高密度90W-6Ni-4Mn合金。研究发现90W-6Ni-4Mn合金制品可以实现近净成形,且新型两步气氛烧结工艺既能还原W、Ni氧化物又能避免MnO的产生,制得的合金样品相对密度达99.2%,粘结相分布均匀,W-W连接度低。通过微观组织与断口形貌分析发现,化学镀镍能促进钨骨架的活化烧结提高合金致密度,同时还能使粘结相实现均匀分布。且具有低W-W连接度的90W-6Ni-4Mn合金由于W-W弱界面的减少,失效速率减缓,从而使其拥有1 583.4 MPa的抗压强度与968 MPa的抗拉强度,塑性与韧性可分别达到21.5%与5.3 J/cm^(2)。

As a new generation of kinetic energy armor-piercing projectile materials,the preparation of 90W-Ni-Mn alloy has the problems of high W-W contiguity,low sintering density and high processing cost.In order to solve these problems,the tungsten powder is treated with electroless nickel plating,and take shape using the feed-stock by injection molding process,and then cooperate with the self-developed new argon-argon hydrogen two-step sintering process to prepare a 90W-6Ni-4Mn alloy with low W-W contiguity.Experiments show that 90W-6Ni-4Mn alloy can be nearly net shaped,and the new sintering process can not only reduce W and Ni oxides content,but also avoid the generation of MnO.The relative density of the prepared sample reaches as high as 99.2%,the bonding phase distribution is uniform,and the W-W contiguity is low.Through microstructure and fracture mor-phology analysis,it is found that electroless nickel plating can promote the activation and sintering of tungsten skel-eton,improving the density of alloy and promoting the uniform distribution of bonded phases.The 90W-6Ni-4Mn alloy as made with low W-W contiguity slows down the failure rate due to the reduction of the weak interface of W-W,resulting in the compressive strength and tensile strength are as high as 1583.4 MPa and 968 MPa,and the well plasticity and toughness of 21.5%and 5.3 J/cm^(2),respectively.