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WR13工模具钢中网膜状非金属夹杂物对冲击韧性的影响

Effect of reticular non-metal inclusions on impact toughness of WR13 tool and die steels

  • 摘要: 为探究连续状夹杂物网膜对WR13工模具钢冲击性能的影响,采用氩气雾化制备WR13合金粉,经热等静压烧结成形。以氧含量(质量分数)较低的进口WR13合金粉及对应锭材为对照,借助氧氮氢分析仪、激光粒度仪、扫描电镜和摆锤冲击试验机,从微观表征到力学性能开展系统对比研究。结果表明:夹杂物网膜的形成与合金粉末粒径-氧含量耦合效应密切相关,仅在小粒径、高氧含量合金粉末制备的锭材中发现由Al2O3颗粒形成的夹杂物网膜。这种网膜结构破坏了基体间的冶金结合,同时因其与基体的形变不匹配,导致应力集中,进而成为裂纹萌生的首要诱因。不含连续状夹杂物网膜的锭材冲击功可达(17.50±3.08) J,含有连续状夹杂物网膜的锭材冲击功下降至(7.91±3.97) J,并伴有较大波动。锭材中夹杂物网膜尺寸越大,数量越多,裂纹的萌生与扩展越容易,最终导致锭材冲击性能降低且稳定性较差。

     

    Abstract: To explore the influence of the continuous inclusion network on the impact performance of WR13 tool and die steels, the WR13 alloy powders were prepared by argon atomization and formed by hot isostatic pressing sintering. Taking the imported low-oxygen-content WR13 alloy powders (mass fraction) and the corresponding ingots as the contrast, the microstructure and mechanical properties of the WR13 alloy powders and the corresponding ingots were carried out by oxygen-nitrogen-hydrogen analyzer, laser particle size analyzer, scanning electron microscope, and pendulum impact tester. The results demonstrate that the formation of the reticular inclusions is closely related to the coupling effect between alloy powder particle size and oxygen content. The reticular inclusions formed by Al2O3 particles are observed exclusively in ingots prepared by small-sized and high-oxygen-content alloy powders. These inclusions disrupt the metallurgical bonding between the substrates and induce the stress concentration due to the deformation mismatch with the substrates, serving as the primary initiators of crack formation. Comparative results show that, the ingots without continuous reticular inclusions achieve the impact energy of (17.5±3.08) J, whereas those containing such inclusions exhibit the reduced impact energy of (7.9±3.97) J, with significant fluctuations. Fracture images reveal that, the larger the inclusion size and the greater the inclusion quantity in the ingots, the easier it is for the cracks to initiate and propagate, ultimately leading to the decrease in impact performance and poor stability of the ingots.

     

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