对系列低碳、超高强度贝氏体钢(LUHSBS)，通过审慎地使用硅、锰、镍等合金元素并有效地控制相变温度、冷却与回火参数，强韧性结合良好，又冲击能(AKV ≥185 J)与同强度(＞1500 MPa)的高级马氏体钢23MnNiCrMo相比提高三倍以上。强度与韧性增强的根本原因在于组织细化、贝氏体铁素体(BF)中含碳量增加、碳化物消除以及存在较高体积分数的膜状残余奥氏体(AR)。原子力显微镜和扫描隧道显微镜分析证实：钢中不存在损伤韧性的块状AR区。不仅亚单元被超细化，而且超细亚晶粒的平均尺寸小于20 nm以及部分切变单元的平均厚度仅约1.6 nm。所有这些都是影响钢的强度、AR稳定性和AKV的主要原因。此外，对强度与韧性改善的物理机制还进行了深入的分析。
Through judiciously using the silicon, manganese and nickel as the alloying elements and effectively controlling the transformation temperature, cooling and tempering parameters for a series of low alloy ultrahigh strength bainitic steels (LUHSBS), the combination of strength and toughness are very excellent and the impact energy absorption (AKV ≥185 J) has been tripled compared to the previously advanced martensitic steel 23MnNiCrMo with the same strength level (＞1500 MPa). The basic reasons giving rise to the enhancement of strength and toughness consist in the increase of carbon content and the refinement of sublaths in the bainitic ferrite (BF) and the very thin films of retained austenite (AR). It is confirmed by the atomicforce microscope (AFM) and scanning tunneling microscope (STM) that there was no any large bulky areas of AR in the structure which is less stable and will reduce the impact toughness of bainitic steels. Not only is the sublaths is significantly refined, but also the average size of subgrains is less than 20 nm and the average thickness of shear units in a BF lath is only about 1.6 nm. The refinement of microstructure, the enrichment of interstitial atom carbon in BF and the increase of both the dislocation density and the volume fraction of AR are some critical factors that affect the ultimate tensile strength, the stability of AR and the impact energy absorption. Furthermore, the physical mechanism on the improvement of the combination of strength and toughness is in depth discussed.
参考文献
| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] | |
| [8] | |
| [9] | |
| [10] | |
| [11] | |
| [12] | |
| [13] | |
| [14] | |
| [15] | |
| [16] | |
| [17] |
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