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透射电镜(TEM)分析表明,奥氏体热作工具钢的强化相为晶内析出的MC,它与基体存在严格的晶体学取向关系:(111)_(MC)//(111)γ,[110]MC//[110]γ。在700℃时效,MC质点主要在基体中的空位上形核和长大;在800℃时效,MC质点同时在位错网和空位上形核和长大。晶界上存在两种碳化物:M_(23)C_6和M_7C_3。在700℃时效,M_(23)C_6与基体没有取向关系,而在800℃时效,这种碳化物与基体的取向关系为:(111)M_(23)C_6//(111)γ,[110]M_(23)C_6//[110]γ。
Transmission electron microscopy (TEM) analysis showed that the strengthening phase of the austenitic hot work tool steel is a precipitated MC, which has a rigorous crystallographic orientation relationship with the matrix: (111) _ (MC) // (111) [110] MC // [110] γ. At 700 ℃, MC particles mainly nucleate and grow in the vacancy in the matrix. At 800 ℃, the MC particles nucleate and grow on the dislocation network and vacancies at the same time. There are two kinds of carbides on the grain boundaries: M_ (23) C_6 and M_7C_3. There is no orientation relationship between M_ (23) C_6 and the matrix at 700 ℃, whereas the orientation of this matrix with carbide is (111) M_ (23) C_6 // (111) γ, ] M_ (23) C_6 // [110] γ.