Y_2O_3对93WNiFe合金自锐性的影响

Influence of Y_2O_3 on Self-Sharpening of 93WNiFe Alloy

为了提高传统93WNiFe合金在侵彻装甲时的自锐化能力,采用粉末冶金的方法,在传统93WNiFe合金中加入了少量的Y2O3,经过1200℃氢气氛中预烧和1480℃烧结以及1100℃的真空退火热处理后烧结成为93W-Y2O3合金,其密度达到了理论密度的98.74%。静态力学性能测试结果表明:室温下抗拉强度为891MPa,延伸率为20%,保证了其作为穿甲弹战斗部用钨合金材料的基本力学性能;动态力学性能测试结果表明:在应变为0.28。应变率为3500s-1时,93W-Y2O3合金内部出现了明显的裂纹及大量的微裂纹,而裂纹源正是起始于粘结相中的Y2O3陶瓷相。因此,在93W合金粘结相中形成的弥散Y2O3陶瓷相,可以作为钨合金中微裂纹的萌生源来诱发钨合金的剪切失效,进而可以提高对绝热剪切不敏感的93WNiFe合金材料的自锐化能力。

93W-Y2O3 was designed and studied, which was fabricated via pre-sintering at 1200 ℃ in hydrogen, and then sintering at 1480 ℃and finally annealing at 1100 ℃ in vacuum using powder metallurgy routes in order to promote ＂self-sharpening＂ of 93WNiFe penetrator when it penetrates armor. The density of 93W-Y2O3 reaches 98.74% of theory value. After static mechanical properties were tested, the results show that 93W-Y2O3 composite reaches the basic mechanical properties which are required in penetrator with tensile strength of 891 MPa and ductility of 20% elongation. And when dynamic mechanical properties were tested, the results show that apparent cracks and micro-cracks were observed in 93W-Y2O3 composite under the strain of about 0.28 and strain rate of about 3500 s^-1, and the origins of cracks were just Y2O3 phase of 93W-Y2O3 composite. Y2O3 phase of 93W-Y2O3 composite can induce shear failure as origins of cracks of tungsten alloy, improveing further adiabatic shear sensitivity of 93WNiFe composite.