The microstructive and compressive properties of Ti50Al48,Mn2 and Ti50Al48Cr2 alloys are studied in this paper. Existence of x-x+y transformation in TiAl alloys is confirmed by metallographic examination, the transfor...The microstructive and compressive properties of Ti50Al48,Mn2 and Ti50Al48Cr2 alloys are studied in this paper. Existence of x-x+y transformation in TiAl alloys is confirmed by metallographic examination, the transformation temperatures of Ti5()Al48 Mn2 and Ti50Al48Cr2 are 1375 and 1373 C , respectively. After treating within x+y phase field, the microstructure of alloys consists of lamellar zones (I) and bulk rp. The volume ratio of L /rp increases with increasing solution treatment temperature. The third alloying elements of Mn and Cr distribute perferentially over x phase at solution treatment temperatures and result in that x2 and r lamellae become thicker. The yield strength of Ti50Al48Mn2 and Ti50Al48Cr2 alloys decreases and the compressibility increases with increasing rp volume fraction.展开更多
In the present investigation, Ni_（50）Ti_（25）Al_（25）（at.%） mechanically alloyed powder is deposited on carbon steel substrate.Before the coating process, the substrate is heated to temperature ranging from room...In the present investigation, Ni_（50）Ti_（25）Al_（25）（at.%） mechanically alloyed powder is deposited on carbon steel substrate.Before the coating process, the substrate is heated to temperature ranging from room temperature to 400℃. The microstructure, porosity, microhardness, adhesion strength, and corrosion behavior of the coating are investigated at different substrate temperatures. Results show that coating porosity is lower on high temperature surface. Microhardness and adhesion strength of the deposition layer on the substrate without preheating have lower values than with preheating. The polarization test result shows that corrosion performance of the coating is dependent on micro cracks and porosities and the increasing of substrate temperature can improve the quality of coating and corrosion performance.展开更多
文摘The microstructive and compressive properties of Ti50Al48,Mn2 and Ti50Al48Cr2 alloys are studied in this paper. Existence of x-x+y transformation in TiAl alloys is confirmed by metallographic examination, the transformation temperatures of Ti5()Al48 Mn2 and Ti50Al48Cr2 are 1375 and 1373 C , respectively. After treating within x+y phase field, the microstructure of alloys consists of lamellar zones (I) and bulk rp. The volume ratio of L /rp increases with increasing solution treatment temperature. The third alloying elements of Mn and Cr distribute perferentially over x phase at solution treatment temperatures and result in that x2 and r lamellae become thicker. The yield strength of Ti50Al48Mn2 and Ti50Al48Cr2 alloys decreases and the compressibility increases with increasing rp volume fraction.
文摘In the present investigation, Ni_（50）Ti_（25）Al_（25）（at.%） mechanically alloyed powder is deposited on carbon steel substrate.Before the coating process, the substrate is heated to temperature ranging from room temperature to 400℃. The microstructure, porosity, microhardness, adhesion strength, and corrosion behavior of the coating are investigated at different substrate temperatures. Results show that coating porosity is lower on high temperature surface. Microhardness and adhesion strength of the deposition layer on the substrate without preheating have lower values than with preheating. The polarization test result shows that corrosion performance of the coating is dependent on micro cracks and porosities and the increasing of substrate temperature can improve the quality of coating and corrosion performance.
