The Application Of Rapid Heating Technique In The Study Of Elevated Temperature Dynamic Mechanical Behavior Of Titanium Alloy

Based on the off-line and online rapid contact heating technique, a new type ofrapid heating technique is raised. This technique is used in a indirect split bab-bartensile impact test system and an up-to over1000℃high temperature tensile impacttechnique forms. The tensile impact behaviors of DP TC11were investigated underdifferent temperatures ranging from room temperature(RT)to850℃and strain rates of200s-1,1200s-1. Also, the quasi-static tensile experiments of0.001s-1at thecorresponding temperatures were carried out on MTS809materials testing system. Theresults show that the mechanical behaviors of DP TC11is temperature and strain rate dependent. The strength of the material decreases with the increased temperature andthe decreased strain rate. Under dynamic loading conditions, the material exhibits anideal plastic deformation at a temperature of850℃. Under quasi-static loadingconditions the material becomes severe softening at750℃and850℃. The temperatureof300℃and600℃divide the stress-temperature curves into3parts.. Below300℃and above600℃, the strength declines rapidly, while it declines slowly between300℃~600℃. Under quasi-static loading conditions, the elongation of DP TC11increasesslowly below300℃while grows rapidly above600℃. At850℃, the elongationreaches almost45%. Under dynamic loading conditions, the elongation of DP TC11increases relatively slowly and the maximum elongation can not exceed15%. Thetemperature of600℃acts as the transition point of yield ratio. The yield ratio underquasi-static loading conditions is generally lower than that under dynamic loading andincreases with the increased strain rate under dynamic loading. Above600℃, theyield ratio under dynamic loading is almost equal to the condition of quasi-static anddecreases rapidly with the increased temperature.The SEM fractographic observation shows that plastic fracture happens under allloading conditions. The quantity of the voids increases with the increased temperature.At the same temperature, the dimension of voids under dynamic loading are larger thanthe loading condition of quasi-static.Metallographical analysis shows that the grains refine obviously with theincreased temperature under different strain rates and prolongs along the tensiledirection. Dynamic recrystallization is observed at different strain rates under elevatedtemperature.