6-5-4-2高速钢中的贝氏体转变

The Bainite Transformation in 6-5-4-2 High-Speed Steel

用TEM研究了6-5-4-2高速钢经1250℃奥氏体化后于300及250℃等温形成的上、下贝氏体结构,所见两种贝氏体的最终形态都由亚片长大结合而成。上、下贝氏体的宏观惯习面都接近(110)γ,Fe_3C析出始于γ/α相界面。在下贝氏体中发现了相间沉淀的形态特征。两种贝氏体中存在的长大台阶,表明贝氏体长大属台阶机制。

TEM study on 6-5-4-2 High Steed Steel is conducted, thc structure of upper and lower bainites are formed isothermally at 300 and 250℃ after austenizing at 1250℃. The final morphology of the two bainites formed result from the sub-plate growth and combination. The macro-habit plane of the upper and lower bainites lies close to (110)γ. Fe3C is precipitated from the phase interface γ and α at first.The morphological character of inter phase precipitation is observed in the lower baintite. The appearance of growth ledge in the two bainites demonstrates the ledget mechanism of the bainite growth.