添加鎂於低碳鋼SS400中，所形成之介在物可有效抑止沃斯田鐵晶粒成長，本研究探討介在物在高溫下對沃斯田鐵晶界釘紮之效力，藉由高溫共軛焦雷射掃描顯微鏡臨場觀察並研究高溫下介在物與晶界間之交互作用。
針對SS400鋼中介在物進行EDS成分分析，並藉由EBSD菊池線鑑定介在物結構，結果發現複合型介在物比例較非複合型高，並透過Factsage模擬介在物之生成過程。另外根據SEM的結果，MgO或MgO∙Al2O3通常位於中心，而MnS通常在外側，推測MnS會於MgO或MgO∙Al2O3介在物上異質成核。
本實驗使用高溫共軛焦雷射掃描顯微鏡將試片持溫於1250℃，持溫時間10分鐘，透過即時影像計算單位時間內晶界移動量、沃斯田鐵晶粒尺寸等數值，求得晶粒成長速率、晶粒成長驅動力及晶界遷移率。最後藉由比較晶界遷移率得知MgO介在物釘紮力最佳，MgO∙Al2O3-MnS次之，MgO-MnS第三，MnS最差。

The formation of inclusion in low carbon steel SS400 with Magnesium addition can inhibit austenite grain growth efficiently. In this study, we discussed the pinning effect on austenite grain boundary by inclusions at high temperature.
The chemical composition of inclusions was analyzed by SEM-EDS, and then, the identification of inclusions by Kikuchi pattern was obtained by EBSD. And with the help of high temperature confocal laser scanning microscope(HT-CLSM), we investigated and observed the in-situ interaction process between grain boundary and inclusions.
Grain growth velocity, grain growth driving force, and grain growth mobility were calculated by in-situ images. Finally, the grain growth mobility of inclusions was compared. By calculating grain growth mobility, it was found that MgO has the best pinning effect on grain growth, MgO∙Al2O3 is second, MgO-MnS complex is third, and MnS is the worst.

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