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用光镜、电镜及俄歇谱仪对功率密度1×10~3～1.5 ×10~4W/cm~2的激光束扫描后的硬化层特征进行了研究与探讨。四种钢铁材料硬化层的第一个特征是它和基体之间存在一个深台阶式急剧过渡,其硬度落差可高达HV400～600,这是陡峭温度场分布的直接结果。硬化层的第二个特征是碳的局部扩散(10～130μm)。上述两方面因素导致多样化的组织分层以及相应的特征性组织形貌,如球墨周围形成马氏体硬化环带;中碳钢内层出现不同碳浓度的马氏体区及相应形貌;相变区的马氏体与硬化区以外基体珠光体直接搭接,中间无过渡性转变产物;奥氏体晶粒及马氏体组织显著细化以及铸铁表面的快速凝固层形成纤维状的微细莱氏体顺着热流方向呈扇形分布等等。
The characteristics of the hardened layer after laser beam scanning with power density of 1 × 10 ~ 3 ~ 1.5 × 10 ~ 4W / cm ~ 2 were studied by light microscope, electron microscope and Auger spectrometer. The first characteristic of the four hardened layers of steel material is that it has a steep, deep step transition to the substrate with a hardness drop of up to HV400-600 as a direct result of steep temperature field distribution. The second feature of the hardened layer is the localized diffusion of carbon (10-130 μm). The above two factors lead to a variety of organizational stratification and the corresponding features of the organizational morphology, such as around the ductile martensite hardening zone; carbon steel inner layer of martensite with different carbon concentrations and the corresponding morphology; The martensite in the transformation zone and the matrix pearlite directly overlap with the hardening zone without intermediate transitional products; the austenite grains and martensite structure are remarkably refined and the rapid solidified layer on the surface of the cast iron is formed into a fibrous fine Ledebronite fan-shaped distribution along the direction of heat flow and so on.