Tham khảo tài liệu 'titanium part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Properties and Applications 201 There is another quite old alloy that is similar to . It is Ti-8Al-1Mo-1V and this alloy does not have any significant heat treatment response at least in the way that a p alloys have. Consequently it is reasonable to discuss this alloy in conjunction with even though strictly speaking it is an a p alloy from an alloy constitution standpoint. Because of the high aluminum content Ti-8Al-1Mo-1V precipitation hardens by a2 formation. Ti-8Al-1Mo-1V also has a higher modulus of elasticity than any of the a p alloys because of its high aluminum content. As a sheet product it has a yield stress that is 70-140 MPa higher than mill annealed Ti-6Al-4V sheet. Ti-8Al-1Mo-1V was originally considered attractive because of this strength advantage. In fact it was chosen as the principal alloy for the sheet structure of the American supersonic transport SST airplane in the 1960 s. It was during this contemplated application that the significant susceptibility to stress corrosion cracking of this alloy was discovered. As a result of this discovery this alloy has not been considered as attractive for any applications where this limitation could be an issue. Perhaps the most important remaining application for Ti-8Al-1Mo-1V is for fan blades for medium bypass ratio aircraft gas turbines engines. This is an application where high modulus of elasticity and good annealed strength are important characteristics. Today the cost of this alloy because of the difficulty experienced in producing it and the stress corrosion cracking susceptibility have eliminated it from serious consideration for new applications. Nevertheless it is a technologically interesting alloy and deserves to be mentioned here. Fig. . Example of a very large structure used in the bleaching section of the pulp and paper production CP titanium courtesy J. A. Hall 5 Alpha Beta Alloys In this chapter on a p alloys the basic correlations between processing .
