低碳钢固态相变过程的原位观察

利用共焦激光扫描显微镜（CSLM）原位观察了低碳钢升温及降温过程中的固态相变，直接观测出升温时低温铁素体（α）到奥氏体（γ）以及奥氏体（γ）到高温铁素体（δ）的相变温度，和降温时δ到γ以及γ到α的相变温度。结果表明，随着升温速率从75℃／min升至130℃／min，α—γ相变开始温度从961．6℃升至1014．0℃、γ→δ相变开始温度从1351℃升至1386．9℃；降温时随着降温速率的增大（70℃／min增至530℃／min），γ—α相变开始温度从871．6℃降至858．4℃。在升温速率为130℃／min的情况下，随着升温最大值的提高（1300℃至1480℃），γ—α相变温度降低，相变开始温度从895．2℃降至858．4℃。

In-situ Observation of Solid Phase Transformation of a low Carbon Steel

Low carbon steel＇s solid phase transformations in the processes of heating-up and cooling-down were observed in-situ by using a eonfoeal scanning laser microscope （CSLM）. The phase transformation temperatures from ferrite （α） （low temperature） to austenite （T）, then to ferrite （8） （high temperature）, and inversely, can be observed directly by CSLM. The results show that when the heating rate increases from 75℃/min to 130℃/min, the α→γ phase transformation temperature increases from 961.6℃ to 1 014.0℃, and then the γ→δ phase transformation temperature increases from 1 351℃ to 1 386.9℃. In the cooling process, the γ→α phase transformation temperature decreases from 871.6℃ to 858.4℃ as the cooling rate increases from 70℃/min to 530℃/min. At the heating rate of 130℃/min, the γ→α phase transformation temperature decreases from 895.2℃ to 858.4℃, when the maximum heating temperature increases from 1 300℃ to 1 480℃.