热处理对Ti-5331合金板材组织及力学性能的影响

研究了核反应堆壳体用Ti-5331合金热轧板材在不同退火温度下的显微组织与力学性能。结果表明:Ti-5331合金板材在相变点以下随着退火温度的升高,初生α相含量逐渐减少,β转变相含量明显增加。当退火温度为700℃时,开始发生静态再结晶,800℃时为等轴组织,900℃时为双态组织,950℃时为网篮组织。随着退火温度的升高,合金板材的抗拉强度先下降后上升,屈服强度呈下降趋势,屈强比逐渐减小;当退火温度在相变点以下时,板材冲击韧性随退火温度升高呈上升趋势,当超过相变点后冲击韧性急剧下降;退火温度对塑性影响较小。经900℃×1 h/AC退火处理的Ti-5331合金板材有着较好的综合性能,抗拉强度为920 MPa,延伸率为15%,V型缺口冲击韧性达到93 J/cm^2。

Effect of Heat Treatment on Microstructure and Mechanical Properties of Ti-5331 Alloy Plate

The effects of heat treatment on the microstructure,tensile property,impact toughness of the hot rolled Ti-5331 alloy plate,which used for the nuclear reactor shells were investigated. The results show that the content of primary α phase decreases and the content of β phase increases with the increase of the annealing temperature below the phase transition point of Ti-5331 alloy. Annealing at 700 ℃,the static recrystallization begins to occur. The microstructure shows the equiaxed and the duplex feature after 800 ℃ and 900 ℃ annealing,respectively. Above 950 ℃ annealing,it shows the widmanstatten microstructure. With the increase of the annealing temperature,the fracture strength of the alloy plate first decreases and then increases,the yield strength and the yield ratio both gradually decreases. Additionally,the impact toughness of the alloy plate first increases and then decreases with the increasing of the annealing temperature,and the annealing temperature has little influence on the plasticity of the Ti-5331 alloy plate. At 900 ℃ × 1 h/AC annealing,Ti-5331 alloy plate has the excellent comprehensive performance,for the tensile strength is about 920 MPa,the elongation is 15%,and V-notch impact toughness can reach 93 J/cm^2.