Titanium Alloy Temperature And Pressure Forming Technology

Since always, high use cost is the main factor of impeding the wide using of titaniumalloy with outstanding performance. In order to seek a productive technology which canrealize low cost and high performance for titanium alloy, a research of experiment andnumerical simulation on titanium alloy warm compaction was applied to explore thefeasibility of warm compaction on titanium alloy.The experimental research of titanium alloy warm compaction shows that , when themixed powder which was made up of titanium alloy powder of 4-1 granule proportion andstearic acid barium of 0.4 mass fraction percent was pressed into the titanium alloycompaction ofΦ10×30 in 120℃and 500MPa, it can obtain the highest density of 3.82cm3, above or below the temperature the density was reduced. Among them, the die-walllubrication can make best lubricant content of powder down to 0.2%; the way of two-waypressing successfully realized the compaction of titanium alloy test bars and awarded thehighest density of 4.0 g/cm3 in 110℃and 700MPa,so the effect was obvious.In the same condition, the compaction sintered with presintering and sintered in 1350℃can improve the sintered density about 0.02 g/cm3 and 0.015 g/cm3 respectively than itsintered without presintering and in 1250℃. The density of titanium alloy test bar sinteredwith presintering in 1350℃can reach the maximum of 4.36 g/cm3,which achieve the theorydensity of 98.41%.The change rule of Mechanical properties with temperature is the same with compactionand sintered body. So the titanium alloy test bar pressed in 110℃can obtain the best tensilestrength of 985MPa and the elongation of 11.06%, whoes comprehensive mechanicsperformance is the best.In order to study the titanium alloy warm compaction technology from another point ofview, the software MSC MARC 2010 was used to simulate the process of pressing, the resultsshowed that: the phenomenon of die-wall friction make powder surrounding flow axiallydelayed also reflected in characteristics of density distribution; stress conditions at the corners make the powder near the mold radially flow from the edge to center,the far directions theopposite, the density distribution of concentration in corners is also related with it. Along withthe increase of pressure during warm compaction, the relative density change rule isconsistent with experimental performance, temperature of peripheral powder contacting withmold has the phenomenon of rising because of plastic working and friction. Die-walllubrication can reduce the friction coefficient between powder and die-wall, two-way pressingnarrowed the density difference of compaction along the pressing direction,both hadeffectively improved the densification effect of titanium alloy warm compaction, tallied withexperiment results.Through the discussing on densification mechanism of titanium alloy warm compaction,the useful guidance on formulating of warm pressing craft had been obtained. As an exampleshows, the titanium alloy warm compaction craft is of practical value.