Effects of Shaping Conditions on the Microstructure and the Mechanical Property of the Al2O3-YAG Eutectic Composite Produced by Melting the Al2O3-YAP Eutectic Structure
Effects of Shaping Conditions on the Microstructure and the Mechanical Property of the Al2O3-YAG Eutectic Composite Produced by Melting the Al2O3-YAP Eutectic Structure
复制标题
成型条件对Al2O3-YAP共晶组织熔化制备Al2O3-YAG共晶复合材料显微组织和力学性能的影响
DOI：
10.2320/matertrans.mb200705
复制
发表时间：
2007
影响因子：
1.2
通讯作者：
Asako Kawaguchi
中科院分区：
文献类型：
--
作者：
T. Nagira;H. Yasuda;Takumi Sakimura;Asako Kawaguchi
当Al_2 O_3-雅普亚稳共晶体系被加热到亚稳共晶温度以上但低于平衡共晶温度时，形成过冷熔体。在平衡路径上的凝固伴随着亚稳共晶系统的熔化，产生细小均匀的共晶组织。提出了一种新的过冷熔体成形凝固工艺。本文研究了初始Al_2O_3-雅普共晶颗粒尺寸、成形压力和最高温度保温时间对Al_2O_3-YAG压坯显微组织和力学性能的影响，以优化成形条件。与直径为20 ~ 45 mm的Al 2 O3-雅普共晶颗粒相比，直径小于20 mm的Al 2 O3-雅普共晶颗粒制备的Al 2 O3-YAG压坯具有更高的抗弯强度和更小的孔隙率。在10 MPa的成形压力和60 s的保温时间下，孔隙率的体积分数约为4%。Al 2 O3-YAG压坯的抗弯强度随着保温时间的增加而降低，这是由于片层间距的增加。对于直径小于20 mm的Al 2 O3-雅普共晶颗粒，10 MPa的低成型压力和60 s的短保温时间足以合成致密的Al 2 O3-YAG压坯。因此，使用通过熔化Al 2 O 3-雅普亚稳共晶系统产生的过冷熔体的凝固技术具有良好的成形优势。[doi：10.2320/matertrans.MB200705]
When the Al2O3-YAP metastable eutectic system was heated above the metastable eutectic temperature but below the equilibrium eutectic temperature, undercooled melt was formed. Solidification in the equilibrium path accompanied the melting of the metastable eutectic system, resulting in a fine and uniform eutectic structure. A novel solidification process using undercooled melt formation was developed. In this paper, the influences of the initial Al2O3-YAP eutectic particle size, forming pressure and holding time at the maximum temperature on the microstructure and/or the mechanical property of the Al2O3-YAG compact were examined to optimize the forming conditions. The Al2O3-YAG compact produced from the Al2O3-YAP eutectic particles with diameters less than 20 mm exhibited a higher flexural strength and the smaller porosity as compared to that produced from Al2O3-YAP eutectic particles with diameters ranging from 20 mm to 45 mm. The volume fraction of the porosity was approximately 4% under a forming pressure of 10 MPa and a holding time of 60 s. The flexural strength of the Al2O3-YAG compact decreased with the increase in the holding time due to the increase in the lamellar spacing. For Al2O3-YAP eutectic particles with diameters less than 20 mm, a low forming pressure of 10 MPa and a short holding time of 60 s were sufficient to synthesize a dense Al2O3-YAG compact. Thus, the solidification technique that uses undercooled melt produced by melting the Al2O3-YAP metastable eutectic system has good advantages for shaping. [doi:10.2320/matertrans.MB200705]