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工业纯铁与共析碳钢表面渗硼层先在炉中处理,以获得共晶组织,然后以高能密度激光束扫描;被激光熔化的金属在冷基底的吸热作用下,以非常高的速度冷却并凝固。实验表明,炉内处理后Fe-B合金层的共晶由α-Fe+Fe_2B二相组成,FeC-B合金层的共晶由α-Fe+Fe_3(C、B)二相组成;共晶中Fe_2B为方棒状和Fe_3(C、B)为片层状。激光熔化激冷后,共晶中的相组成及形貌无改变,但棒间距和片间距相应减小了40及100倍。共晶组织的硬度大幅度增高,每个合金系的共晶组织的硬度与尺寸的关系服从Hall-Petch公式。
Industrial pure iron and eutectoid carbon steel surface boronizing layer first processed in the furnace to obtain eutectic structure, and then high-density laser beam scanning; laser melting metal in the cold substrate endothermic effect at a very high speed Cool and solidify. The experiment shows that the eutectic of Fe-B alloy layer is composed of two phases of α-Fe + Fe_2B and the eutectic of FeC-B alloy layer consists of two phases of α-Fe + Fe_3 (C, B) In Fe_2B square bar and Fe_3 (C, B) lamellar. After laser melting and chilling, the phase composition and morphology of the eutectic did not change, but the rod spacing and the chip spacing were reduced by 40 and 100 times, respectively. The hardness of the eutectic structure is greatly increased. The relationship between the hardness and the size of each alloy eutectic follows the formula of Hall-Petch.