Study On Comprehensive Mechanical Properties Of Titanium Alloy T Type Compound Welds Structural Element

This task roots in Beijing Aerospace Manufacture Research institute about study on comprehensive mechanical properties of Titanium alloy T type compound welds structural element. The compositive mechanical properties of joint is the important point, because the foundation data will be in favor of advancing the welding processs. This research is carried out by follow five steps:①study the tensile mechanical properties of two kinds of welding process, the points are Young's modulu,yield strength,tensile strength.②Compression experimen of T plant the points are compressive strength,compressive yield strength.③T structure three spot curving experiments, the targets are biggest bend angle,maxiumal load,biggest break displacement.④Study the fatigue life under two kinds of stress in T weld joint fatigue properties experiment.⑤Reserch the residual stress plan and influence in the T structure.The important outcomes are as follows:①Tension: The intensity of compound welding process BP16 is high (The yield strength compares the electron-beam welding craft more 18%),the plasticity is bad (The elongation ratio compares the electron-beam welding A3 craft lower 23%).②Compression: The welding structural element ultimate strength compares the parent metal lower 28-52%; in five technics BP16-1 is the best, TNCZ2 is the badest, the most different under 19%( ultimate strength).③Curving:Ti-17 is the best at most greatly nominal stress of break, but BP16-6 is opposite, the difference is 21% at stree, but it is equal at bend angle.④Fatigue:The fatigue life of electron-beam-welding precede compound welding.⑤Residual stress: After welding, the stress distribution is symmetrical at x , y direction of original state plate; the curves of residual stress overlap at x , z direction of rid. The test specimen residual stress presents wave in the front face, the reverse side is alwayse negative value.