热等静压成形Ti-45Al-7Nb-0.3W合金热轧板材的超塑性变形行为  

Superplastic deformation behavior of hot isostatic pressed Ti-45Al-7Nb-0.3W hot-rolled alloy sheet

作　　者：彭昱钦 李应新 梁霄鹏[1] 李慧中[1] 车逸轩 郭昕明 PENG Yuqin;LI Yingxin;LIANG Xiaopeng;LI Huizhong;CHE Yixuan;GUO Xinming(School of Materials Science and Engineering,Central South University,Changsha 410083,China;Zhuzhou Ruideer Metallurgy Equipment Manufacturing Co.,Ltd.,Zhuzhou 412000,China)

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]株洲瑞德尔智能装备有限公司,株洲412000

出　　处：《粉末冶金材料科学与工程》2022年第4期419-425,共7页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金资助项目(51774335)。

摘　　要：对热等静压法制备的 Ti-45Al-7Nb-0.3W 合金进行 1 270 ℃热轧,得到合金板材,利用扫描电镜(SEM)观察板材的显微组织。对合金板材进行 950 ℃、初始应变速率为 1×10^(-4)s^(-1)的高温拉伸实验,根据拉伸应力-应变曲线与拉伸性能,以及拉伸断裂后的显微组织演变与拉伸断口形貌,研究轧制变形合金板材的超塑性变形行为。结果表明:热等静压态合金经热轧后,由近 γ 组织转变为双态组织,并随轧制变形量增加,热轧板材的平均晶粒尺寸减小,伸长率增加。当变形量为 61%时,平均晶粒尺寸最小,为 9.8 μm,板材伸长率最大,达到 367.5%,抗拉强度为 131 MPa。继续增加轧制变形量时,板材晶粒长大,伸长率降低。板材在超塑性变形过程中,α/γ 层片晶团旋转分解,并在其周围产生大量动态再结晶晶粒。板材的超塑性变形机制为晶界滑移与动态再结晶。The hot isostatic pressed (HIP) Ti-45Al-7Nb-0.3W alloy sheet prepared by hot-rolled at 1 270 ℃, and the microstructure of the alloy sheet was investigated by scanning electron microscopy (SEM). High-temperature tensile experiments at 950 ℃ with an initial strain rate of 1×10^(-4)s^(-1)were performed. According to the tensile stress-strain curve and tensile properties, as well as the microstructure evolution and tensile fracture morphology after tensile fracture,the superplastic deformation (SPF) behavior of the alloy sheet with rolling deformation was studied. The results show that after rolling, the microstructure of as-HIPed alloy sheet changes from near-γ microstructure to duplex microstructure.And the average grain size of the sheet decreases and the elongation increases with the increase of rolling reductions.When the rolling reduction is 61%, the average grain size of the hot-rolled sheet is the smallest (9.8 μm), the elongation of the sheet is the largest (367.5%), and the tensile strength is 131 MPa. Continue to increase the rolling deformation, the grain size of the sheet grows, and the elongation decreases. During the SPF, the α/γ lamellar colonies rotate and decompose, and a large number of dynamically recrystallized (DRX) grains are generated around them. The superplastic mechanism of the plates is grain boundary slip (GBS) and DRX.

关 键 词：TIAL基合金 超塑性 包套轧制 显微组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]