Recent work on Ti_3Al base alloy,TAC-1, developed in CISRI, including investigations of effects of modification in alloying and TMP on microstructural characteristics and mechanical behaviour,indicates that alloy TAC ...Recent work on Ti_3Al base alloy,TAC-1, developed in CISRI, including investigations of effects of modification in alloying and TMP on microstructural characteristics and mechanical behaviour,indicates that alloy TAC -1 is very promising structural material for a number of elevated temperature applications. Stuody dealing with a reverse relation between RT ductility and toughness found on TiA base alloy, TAC-2, led to development of a special heat treatment technique for producing a fine filly lamellar microstructure (FFL), which gives a high and balancing ductility and toughness. This is also of significance for promoting engineering applications of this alloy.展开更多
1.IntroductionThe research of the TD1 and TD2 al-loys based on intermetallic compound TiAl,which possesses high temperature capabilityfrom 650 to 700℃ was conducted.However,the limitation used at high temperature isi...1.IntroductionThe research of the TD1 and TD2 al-loys based on intermetallic compound TiAl,which possesses high temperature capabilityfrom 650 to 700℃ was conducted.However,the limitation used at high temperature isimposed by oxidation and degradation ofcreep strength,and relatively little know-展开更多
Both hydrogen induced cracking and overload crack initiated at same characteristic distance, r~*,within the plastic zone along the slip line when the plastic zone developed to a critical ex- tent.For the overload crac...Both hydrogen induced cracking and overload crack initiated at same characteristic distance, r~*,within the plastic zone along the slip line when the plastic zone developed to a critical ex- tent.For the overload crack. K_(IC)=αr~*^(1/2)[σ_F^((n+1)/2n)/σ_(ys)^((1-n)/2n)],σ_F=σ_0+g[2μbσ_(th)/π~2L(1-v)]^(1/2) For the hydrogen induced cracking: K_(IH)=αr~*^(1/2)[σ_F(H)^((n+1)/2n)/σ_(ys)(H)^((1-n)/2n)], σ_F(H)={σ_0(H)+g[2μbσ_(th)(H)/π~2L(1-v)]^(1/2)}/k Hydrogen pomoting the dislocation multiplication and motion would result in σ_0(H)<σ_0, k>1,Therefore,hydrogen promoting the cleavage fracture in titanum aluminide can be due to that hydrogen facilitates the local plastic deformation,which results in σ_F(H)<σ_F and then K_(IH)<K_(IC).展开更多
文摘Recent work on Ti_3Al base alloy,TAC-1, developed in CISRI, including investigations of effects of modification in alloying and TMP on microstructural characteristics and mechanical behaviour,indicates that alloy TAC -1 is very promising structural material for a number of elevated temperature applications. Stuody dealing with a reverse relation between RT ductility and toughness found on TiA base alloy, TAC-2, led to development of a special heat treatment technique for producing a fine filly lamellar microstructure (FFL), which gives a high and balancing ductility and toughness. This is also of significance for promoting engineering applications of this alloy.
文摘1.IntroductionThe research of the TD1 and TD2 al-loys based on intermetallic compound TiAl,which possesses high temperature capabilityfrom 650 to 700℃ was conducted.However,the limitation used at high temperature isimposed by oxidation and degradation ofcreep strength,and relatively little know-
文摘Both hydrogen induced cracking and overload crack initiated at same characteristic distance, r~*,within the plastic zone along the slip line when the plastic zone developed to a critical ex- tent.For the overload crack. K_(IC)=αr~*^(1/2)[σ_F^((n+1)/2n)/σ_(ys)^((1-n)/2n)],σ_F=σ_0+g[2μbσ_(th)/π~2L(1-v)]^(1/2) For the hydrogen induced cracking: K_(IH)=αr~*^(1/2)[σ_F(H)^((n+1)/2n)/σ_(ys)(H)^((1-n)/2n)], σ_F(H)={σ_0(H)+g[2μbσ_(th)(H)/π~2L(1-v)]^(1/2)}/k Hydrogen pomoting the dislocation multiplication and motion would result in σ_0(H)<σ_0, k>1,Therefore,hydrogen promoting the cleavage fracture in titanum aluminide can be due to that hydrogen facilitates the local plastic deformation,which results in σ_F(H)<σ_F and then K_(IH)<K_(IC).
