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采用热等静压技术(HIP)在1160℃、100MPa条件下制备出Cr_3C_2/Ni_3Al复合材料,研究了Cr_3C_2/Ni_3Al复合材料的微观组织和相组成。结果表明,Cr_3C_2初始颗粒首先溶解成Cr和C原子,并往基体中扩散;冷却过程中,溶解的Cr和C原子转化为稳定的Cr_7C_3结构;由于Ni_3Al合金中的Fe易与C形成稳定碳化物,促使Fe原子从基体中往Cr_7C_3结构中发生上坡扩散,并取代Cr_7C_3结构中的部分Cr原子形成M_7C_3(M为Cr、Fe,余同)结构的扩散相。当Cr_3C_2初始颗粒较大时,在高温过程中,Cr_3C_2颗粒未能全部溶解,而未溶解的Cr_3C_2颗粒芯部在冷却过程中仍保持为Cr_3C_2结构。该条件下制备的Cr_3C_2/Ni_3Al复合材料主要由Cr_3C_2硬芯相、M_7C_3扩散相和γ′-Ni_3Al基材相组成,其中Cr_3C_2硬芯相和γ′-Ni_3Al基材相通过M_7C_3扩散相形成良好的扩散连接;该结构的复合材料磨损后表面Cr_3C_2颗粒末发生剥落且沟槽在铬碳化物处发生中断,表现出良好的耐磨性。
The Cr3C_2 / Ni_3Al composites were prepared by hot isostatic pressing (HIP) at 1160 ℃ and 100MPa, and the microstructure and phase composition of the Cr_3C_2 / Ni_3Al composites were studied. The results show that the initial Cr 3 C 2 particles first dissolve into Cr and C atoms and diffuse into the matrix. During cooling, the dissolved Cr and C atoms transform into stable Cr_7C_3 structure. Because Fe in Ni_3Al alloy easily forms stable carbides with C , Promoted upward diffusion of Fe atoms from the matrix to Cr_7C_3 structure and replaced part of the Cr atoms in the Cr_7C_3 structure to form a diffusion phase of M_7C_3 (M is Cr, Fe and the rest). When the initial Cr 3 C 2 particles were large, the Cr 3 C 2 particles did not dissolve completely at high temperature, while the core of the undissolved Cr 3 C 2 particles remained Cr 3 C 2 during the cooling process. The Cr_3C_2 / Ni_3Al composites prepared mainly consist of Cr_3C_2 hard core phase, M_7C_3 diffusion phase and γ’-Ni_3Al matrix phase. The Cr_3C_2 hard core phase and the γ’-Ni_3Al matrix phase are well diffused through M_7C_3 phase Diffusion bonding. The Cr3C2 particles on the surface of the composites wear off and the grooves are discontinued at the Cr carbides, showing good wear resistance.