退火对TA1/5052爆炸复合板界面组织与性能的影响

将TA1/5052爆炸焊接复合板在350、400及450 ℃分别保温1、3、6、9 h退火,对退火前后复合板组织和性能进行分析。结果表明:随退火温度升高,原子扩散加剧,界面形成的扩散层逐渐变厚;退火过程中铝易于向钛侧扩散,白色亮带和柯肯达尔孔洞主要位于靠近界面的5052铝合金侧;退火前界面处物相组成为α-Ti、α-Al、TiAl₃,经350、400 ℃退火3 h及450 ℃退火1、3、6、9 h后,物相组成不变。经不同温度退火后,复合板界面抗拉强度低于退火前,而断面收缩率和伸长率明显高于退火前。拉伸断口分析表明,复合板TA1侧为以脆性断裂为主、韧性断裂为辅的韧脆混合断裂,5052侧为韧性断裂;复合板在350 ℃退火时界面剪切强度和剥离强度最大,较爆炸态分别增加8.24%和45.68%,随退火温度升高,界面剪切强度和剥离强度降低。退火前后界面结合区硬度均高于基复板两侧硬度,且随离界面距离增加,硬度逐渐降低直至降至钛铝两侧母材硬度。退火后界面结合区硬度明显低于爆炸态硬度。

Effect of annealing on bonding interface microstructure and properties of TA1/5052 explosive welded composite plates

TA1/5052 explosive welded composite plates were annealed at 350, 400 and 450 ℃ for 1, 3, 6 and 9 h, respectively. The microstructure and properties of the composite plates before and after annealing were studied. The results show that with the increase of annealing temperature, atomic diffusion intensifies and the diffusion layer formed at the interface becomes thicker. During annealing process, aluminum diffuses easily to the titanium side, while the bright white band and Kirkendall hole are mainly located in the side of 5052 aluminum alloy near the interface. The phase composition at the interface before annealing is α-Ti, α-Al and TiAl₃. After annealing at 350, 400 ℃ for 3 h and at 450 ℃ for 1, 3, 6, and 9 h, the phase composition is unchanged. After annealing at different temperatures, the tensile strength of the interface of the composite plates is lower than that before annealing, while the area shrinkage and elongation are significantly higher than that before annealing. The analysis of tensile fracture shows that the TAl side is ductile brittle mixed fracture with brittle fracture as the main and ductile fracture as the auxiliary, and the 5052 side is ductile fracture. When annealed at 350 ℃, the interfacial shear strength and peel strength of the composite plates are the highest, which is increased by 8.24% and 45.68%, respectively, compared with the explosion state. With the increase of annealing temperature, the interfacial shear strength and peel strength decreases. The hardness of the interface bonding zone before and after annealing is higher than that of both sides of the base plate, and with the increase of the distance from the interface, the hardness gradually decreases to the hardness of the base metal on both sides of Ti/Al. The hardness of the interface bonding zone after annealing is significantly lower than that of the explosion state.