Electron Beam Rapid Prototyping TC18Tensile Deformation Behavior And Deformation Mechanism Of The Research

Titanium alloy has a density, high specific strength, corrosion resistance, smallcoefficient of linear expansion, the nonmagnetic and many other advantages. In recentyears titanium alloys have very important applications in the aerospace, chemical,military, vehicle engineering, biomedical engineering and everyday life. TC18titaniumalloy is a precipitation phase strengthening of the transition type α+β titanium alloy,BT22alloy equivalent of the former Soviet Union, a nominal composition ofTi-5Al-5Mo-5V-1Cr-1Fe. TC18titanium alloy with high strength, hardenability depth,suitable for the manufacture of large-scale air-bearing structure pieces. This papersystematically studied the tensile deformation behavior of the electron beam rapidprototyping TC18titanium alloy.Electron beam rapid prototyping is just the rise of an increase in materialmanufacturing technology. The use of computer-aided design of three-dimensionalmodel of hierarchical processing parts, thereby generating processing flowchart. Usingan electron beam as a heat source, the metal wire is melted, in accordance with thedesign and processing flowchart Drill cumulative use of metallurgical bonding, so thatthe adjacent two layers close integration, until the production of a complete metal parts.This technology is characterized by: high material and energy utilization, productionspeed. Apply to the manufacture and repair of large and medium-sized titanium andother metal parts.This paper systematically studies a the TC18alloy electron beam fuse depositedunder the conditions of rapid prototyping, alloy columnar grain growth direction wasdifferent angle and tensile principal stress directions tensile deformation behavior ofthe material and its damage deformation mechanisms and different heat treatment TC18microscopic Organization and microhardness. The findings, presented differentangles between the columnar grain growth direction tensile principal stress directionhas an important effect on the tensile deformation behavior of the material. When thesampling direction and horizontally in the direction of the growth of columnar crystalsplastic Preferably, the fracture mode is apparent toughness fracture; when the samplingdirection of columnar crystal growth direction was45°, the strength and ductility ofthe material to achieve a good match; sampling direction with the columnar crystalgrowth direction was90°, materials prone to brittle fracture, the fracture mode wasbrittle intergranular fracture. Reannealing conditions, with increasing annealingtemperature, the reduced primary α-phase volume fraction, aspect ratio decreases,metastable β matrix microhardness; the double annealing conditions, thelow-temperature annealing result in small strips like α phase precipitation the β matrixmicrohardness significantly increased; small strip α grew up with the low-temperatureannealing temperature increases, coarse, dispersion strengthening effect decreases, sothat the β matrix hardness decreased; triple annealing conditions secondheavy-temperature annealing affect the amount of precipitation, the size and shape ofbamboo leaves like an α-phase, β matrix hardness; heavy low-temperature annealingprocess will precipitate the same small strip of secondary α phase, resulting in β matrixmicrohardness increased significantly; render a shift in the relationship for the differenttypes of α-phase. Coarse primary α and a high temperature α precipitated relative βmatrix hardness is less affected, and the strip of fine α-phase precipitated in thelow-temperature annealing process can significantly increase the microhardness of theβ matrix, such cryogenic α precipitation phase of the finer size, the greater the numbermore and more obvious strengthening effect on β matrix.