The effects of sub-transus(α+β)annealing treatment(ST),followed by single aging(SA)or duplex aging(DA)on the microstructural evolution and mechanical properties of near-βTi-4Al-1Sn-2Zr-5Mo-8V-2.5Cr(mass fraction,%)...The effects of sub-transus(α+β)annealing treatment(ST),followed by single aging(SA)or duplex aging(DA)on the microstructural evolution and mechanical properties of near-βTi-4Al-1Sn-2Zr-5Mo-8V-2.5Cr(mass fraction,%)alloy were investigated using optical microscopy,scanning electron microscopy,and transmission electron microscopy.The results show that the finer secondaryαphase precipitates in the alloy after DA than SA(e.g.,149 nm for SA and 69 nm for DA,both after ST at 720℃).The main reason is that the pre-aging step(300℃)in the DA process leads to the formation of intermediateωphase nanoparticles,which assist in the nucleation of the acicular secondaryαphase precipitates.In addition,the strength of the alloy after DA is higher than that of SA at the specific ST temperature.A good combination is achieved in the alloy subjected to ST at 750℃,followed by DA(UTS:1450 MPa,EL:3.87%),which is due to the precipitation of nanoscale secondaryαphase by DA.In conclusion,DA is a feasible process for this new near-βtitanium alloy.展开更多
The development and research of titanium cast alloy and its casting technology, especially its application in aeronautical industry in China are presented. The technology of molding, melting and casting of titanium al...The development and research of titanium cast alloy and its casting technology, especially its application in aeronautical industry in China are presented. The technology of molding, melting and casting of titanium alloy, casting quality control are introduced. The existing problems and development trend in titanium alloy casting technology are also discussed.展开更多
Microstructures and tensile properties of a newβhigh-strength titanium alloy Ti-5321(Ti-5 Al-3 Mo-3 V-2 Zr-2 Cr-1 Nb-1 Fe)were investigated in this study.Four microstructures,including equiaxed microstructure(EM),bim...Microstructures and tensile properties of a newβhigh-strength titanium alloy Ti-5321(Ti-5 Al-3 Mo-3 V-2 Zr-2 Cr-1 Nb-1 Fe)were investigated in this study.Four microstructures,including equiaxed microstructure(EM),bimodal microstructure(BM),basket-weave microstructure(WM)and lamellar microstructure(LM),were tailored by changing the forging process,and the influences of different microstructures on tensile properties were also analyzed.The results indicated that Ti-5321 exhibits a better combination of strength and ductility,compared to Ti-5553,Ti-1023,BT22 and Ti15-3.The ultimate tensile strength,total elongation and reduction in area could be achieved in a range of 1200-1300 MPa,10%-15%and40%-60%,respectively.The influences of variant selection on the tensile properties in Ti-5321 alloy were also analyzed.Afterβforging and solution treatment,αphase maintained strictly Burgers orientation relation with adjacentβphase.Morphological features of the fractography in BM and LM were also explored to further explain the tensile properties and the fracture mode of Ti-5321 alloy.展开更多
基金the financial supports from the Key Research and Development Program of Shanxi Province,China(Nos.201903D421084,201903D121056)the National Natural Science Foundation of China(Nos.52171122,52071228,51901151)。
文摘The effects of sub-transus(α+β)annealing treatment(ST),followed by single aging(SA)or duplex aging(DA)on the microstructural evolution and mechanical properties of near-βTi-4Al-1Sn-2Zr-5Mo-8V-2.5Cr(mass fraction,%)alloy were investigated using optical microscopy,scanning electron microscopy,and transmission electron microscopy.The results show that the finer secondaryαphase precipitates in the alloy after DA than SA(e.g.,149 nm for SA and 69 nm for DA,both after ST at 720℃).The main reason is that the pre-aging step(300℃)in the DA process leads to the formation of intermediateωphase nanoparticles,which assist in the nucleation of the acicular secondaryαphase precipitates.In addition,the strength of the alloy after DA is higher than that of SA at the specific ST temperature.A good combination is achieved in the alloy subjected to ST at 750℃,followed by DA(UTS:1450 MPa,EL:3.87%),which is due to the precipitation of nanoscale secondaryαphase by DA.In conclusion,DA is a feasible process for this new near-βtitanium alloy.
基金The paper is support by Foundation Key Project of Yunnan:The Study on inoculated theory and reliability of low carbonductile iron, NO. 1999E0004Z
文摘The development and research of titanium cast alloy and its casting technology, especially its application in aeronautical industry in China are presented. The technology of molding, melting and casting of titanium alloy, casting quality control are introduced. The existing problems and development trend in titanium alloy casting technology are also discussed.
基金financially supported by the International Science and Technology Cooperation Program of China(No.2015DFA51430)the National Natural Science Foundation of China(No.51471136)。
文摘Microstructures and tensile properties of a newβhigh-strength titanium alloy Ti-5321(Ti-5 Al-3 Mo-3 V-2 Zr-2 Cr-1 Nb-1 Fe)were investigated in this study.Four microstructures,including equiaxed microstructure(EM),bimodal microstructure(BM),basket-weave microstructure(WM)and lamellar microstructure(LM),were tailored by changing the forging process,and the influences of different microstructures on tensile properties were also analyzed.The results indicated that Ti-5321 exhibits a better combination of strength and ductility,compared to Ti-5553,Ti-1023,BT22 and Ti15-3.The ultimate tensile strength,total elongation and reduction in area could be achieved in a range of 1200-1300 MPa,10%-15%and40%-60%,respectively.The influences of variant selection on the tensile properties in Ti-5321 alloy were also analyzed.Afterβforging and solution treatment,αphase maintained strictly Burgers orientation relation with adjacentβphase.Morphological features of the fractography in BM and LM were also explored to further explain the tensile properties and the fracture mode of Ti-5321 alloy.
