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采用表面机械磨擦处理(SMGT)在Fe-20Mn-3Al-3Si钢的表面制备梯度相变强化层,并研究了该强化层的微观组织和硬度.结果表明,在SMGT过程中,Fe-20Mn-3Al-3Si钢的表层非常容易发生γ→ε→α马氏体相变.SMGT相变受晶粒取向和外力的共同影响:在小载荷SMGT下,晶粒的{111}或者{110}晶面越靠近试样的表面越容易形成片条状组织;在大载荷SMGT下,表层晶粒严重细化,次表层中片条组织最多,然后片条组织数量逐渐减少.室温车削形成的强化层厚度大于400μm,硬度在表面最高(450 HV),然后随深度增加而逐渐下降至基体硬度(约220 HV).另外,SMGT强化层的热稳定性高,经400℃,1 h退火后其微观组织和硬度基本不变.
The surface modification of Fe-20Mn-3Al-3Si steel with SMGT was carried out and the microstructure and hardness of the strengthened layer were investigated.The results show that during the SMGT process, the Fe-20Mn- The surface layer of 3Al-3Si steel is very prone to γ → ε → α martensitic transformation. The phase transition of SMGT is affected by both grain orientation and external force: Under the small load of SMGT, {111} or {110} The closer the surface to the specimen, the easier it is to form lamellar structure. Under the high load of SMGT, the grain of the surface layer is severely refined, and the number of laths in the subsurface layer is the largest, and then the number of lamellae is reduced gradually. The thickness is greater than 400μm and the hardness is the highest at the surface (450 HV), and then gradually decreases to the hardness of the matrix (about 220 HV) as the depth increases. In addition, the thermal stability of the SMGT strengthened layer is high after annealed at 400 ℃ for 1 h, The organization and hardness are basically unchanged.