板片麻田散鐵及沃斯田鐵在440C合金鋼之回火相變態研究

• Main Authors: Choh-Hsuan Wang, 王旨玄
• Other Authors: J. R. Yang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/43419137137668869049

碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 91 === It is unusual that the MS Temperature of AISI 440C studied in this work is much lower than the room temperature, because the carbon and chromium contents in the stead are respectively 1.04 and 17.4wt%. After quenching into liquid nitrogen, we obtained plate martensite phase which had a burst formation with Zig-Zag morphology. Attempts of this work are to elucidate the complex tempered structure and the decomposed matrix after a double tempering treatment. The results show that the plate martensite contains twinned substructures with an axis-angle pair of {112}/180∘﹔besides, the different types carbides precipitate from martensite matrix and have different orientation relationships with the tempered matrix. In the other hand, the characteristics martensitic transformation and after multi-tempering cycles have been investigated using a Dilatrometric III RDP deformation dilatometer of Theta Industries. The results show that the MS temperature gradually rises with increasing the repeated cycling numbers, and finally austenite transformation into ferrite and carbides, little by little.