摘要
利用ＡＴＥＭ研究了铁基合金Ｆｅ－Ｃｒ－Ｗ－Ｎｉ－Ｃ（ω（％）为１０：５：１：１：１）激光熔覆组织的相结构特征及高温时效时亚稳相转变过程．结果表明熔覆组织为过共晶组织，凝固领先相为Ｍ_７Ｃ_３碳化物，枝晶间共晶为γ－奥氏体及Ｍ_７Ｃ_３，γ为具有较高合金元素过饱和含量的亚稳相，Ｍ_７，Ｃ_３（Ｍ＝Ｃｒ，Ｆｅ，Ｗ等）为六方结构的 Ｃｒ基合金碳化物．高温时效过程中熔覆组织存在 Ｍ_７Ｃ_３＋γ→Ｍ_(２３) Ｃ_６及Ｍ_７ Ｃ_３＋ γ→Ｍ_６ Ｃ的原位转变，同时在非平衡γ中析出 Ｍ_(２３) Ｃ６、 Ｍ_２ Ｃ与 ＭＣ碳化物．熔覆组织具有较高的显微硬度（ＨＶ９２０_(０．２)）并存在显著的二次硬化特征，二次硬化峰值温度及峰值硬度分别为７００℃及ＨＶ１１６０_(０．２)此外，熔覆组织还具有较高的冲击磨损性能．
In situ synthesis of Fe - Cr - W - Ni - C alloys on a low alloy steel substrate by a high power continous wave CO_2 laser cladding were investigated by an analytical electron microscopy with EDAX and EELS. The clad coating consisted of hyper - eutectic microstructure, i. e., M_7C_3 + (γ + M_7C_3 ). γ -- austenite is meta - phase with extended solid solution of alloying elements. During thermally treated at 973K x 1 hour, the precipitation of M_(23) C_6, M_2C and MC from austenite and in situ transformation of dentritic M_7C_3 + rM_(23)C_6 and eutectic M_7C_3 + rM_6 C were observed. The laser - clad microstructure was of secondary hardening character, and the corresponding peak hardening temperature and peak baldness was 973 K and HV_(0.2) 1160 respectively. The laser - clad microstructure also reveals superior impact wear resistance.
出处
《材料科学与工艺》
EI
CAS
CSCD
1999年第2期22-26,共5页
Materials Science and Technology
