关键词: 拉伸强度, 蠕变, 多晶, 石墨, 石墨化

Abstract: The tensile creep was investigated on a polycrystalline graphite material.A specimen before and after creep was analyzed by RAM ANOR U1000 Raman Spectrum,and the varia- tion of pores on longitudinal profile by SEM observed.The results indicate that for a polycrystalline material creep does not take place obviously at 1700℃ and 0.7MPa stress.On ini- tial creep step,the relations can be expressed as ε-ε0=Atn. Under the conditions of different temperatures and stresses,the exponent n varies from 0.485 to 0.8.Under the same stress,n increases as the temperature is raised,The Raman spectrum analysis and SEM analysis show that after the polycrystalline graphite creeped, graphitization degree is increased and pores are multiplied and enlarged.

Key words: tensile strength, creep (metallurgy), polycrystals, graphite, graphitization