| The technology of LDR has accomplished effective and fast repair for titanium alloy parts solved the problem of repair, and promoted the development of the aerospace, shipbuilding and other industries. In this paper, the significance of the subject of LDR techniques are described, microstructure, micro hardness, tensile properties, fatigue and fracture of laser deposition repaired TA15 titanium alloy for different repair ways and sample states are systematically analyzed and studied by adopting the experimental test and theoretical analysis method.Firstly, the microstructure and hardness are analyzed with optical microscope and micro-hardness tester including the distributions of sizes and shape of grains and hardness distribution curve of cross-section. Tensile tests of TA15 titanium alloy with different repair methods and sample state are carried out and the tensile property is analyzed. The result showed that the micro-hardness from repair area to base material is reduced successively and the tensile strength of repair is higher than the base metal. Both hardness and tensile strength are enhanced after solid solution aging treatment.Secondly, the intermediate value life of TA15 titanium with different repair methods and sample state are measured and analyzed contrastively in lab condition. The result showed that the fatigue life of body specimens is 1.7~1.8 times the groove specimens respectively, 21.8%~54% and 40%~68% of the value of the base material life. The fatigue life of solution aging state can reach 54% and 68% of the base material.Lastly, the appearance of macro and micro fracture are observed by SEM including typical area fracture for tensile and fatigue specimens, secondary crack, fatigue striations and dimple. And the fracture mechanism is analyzed. The result showed that the dimple size of annealing state is larger than base metal. The striations of solution-ageing state are more intensive than the sample of annealed state at the early fatigue crack propagation, but the propagation rate significantly grow faster in the latter stage. |
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