TC4钛合金型材高温拉伸变形组织

Tensile Deformation Microstructure of TC4 Titanium Alloy Profile at High Temperature

对热轧退火态TC4钛合金型材进行了不同变形条件下的高温拉伸试验,采用金相显微镜进行微观组织观察,研究了变形温度、拉伸速率对TC4钛合金组织演变的影响。结果表明,当拉伸速率不变时,随着变形温度升高,组织中的片状α相最先开始向等轴α相转变。随着温度的进一步升高,晶界被打碎,晶界α相也开始发生等轴化,组织由魏氏组织转化为等轴组织;当变形温度恒定时,拉伸速率越低,组织中片状α相和晶界α相的细化程度和等轴化程度越高,并且由魏氏组织向等轴组织转变。

High temperature tensile tests of hot-rolled annealing TC4 titanium alloy profile were carried out at 773 K,993 Kand 1 093 K,respectively with 1 mm/min,0.618 mm/min,0.382 mm/min and 0.236 mm/min.The microstructure of TC4 titanium alloy was observed by metallographic microscope,and the effects of different deformation temperature and strain rate on the microstructure evolution of TC4 titanium alloy were investigated.The results indicate that when the stretching rate is constant,the lamellarαphase in the microstructureis is firstly converted into the equiaxedαphase with the increase of deformation temperature.With the further increase of temperature,the grain boundary is broken,of which theαphase also began to undergo equiaxed transformation,and the microstructure is converted from weissmann microstructure to equiaxed microstructure.When the deformation temperature is constant,with decreasing in the stretching rate,the fineness and equiaxed degree of the laminar and grain boundaryαphases in the microstructure are increased,and the weissmann structure is converted to the equiaxed structure.