包覆叠轧TC4钛合金薄板的组织与力学性能

Microstructure and mechanical properties of TC4 titanium alloy thin sheet by cladding-rolling

选取包覆叠轧工艺生产两种不同规格的TC4钛合金薄板,通过光学显微镜、XRD衍射仪、室温拉伸和高温拉伸性能试验,对两种不同规格的TC4钛合金薄板进行微观组织和力学性能研究。结果表明:经轧制退火后薄板的金相组织由α相与残余β相构成,组织中未见明显的β转变组织,α相的形貌呈现出长条状、等轴状以及块状,α相之间为残余β相。两种规格的薄板的XRD图谱中各角度的α相衍射峰相比β相衍射峰较强,厚度为0.8 mm的薄板在(102)、(200)晶面指数的衍射峰更强。厚度为0.8 mm的薄板的室温强度较厚度为2.0 mm薄板的要高,其抗拉强度最大值为1077 MPa,屈服强度最大值为1029 MPa,两种规格薄板的断后伸长率大致相同,最大值为16.5%。薄板在500℃的抗拉强度较400℃时要低,在变形温度为400℃时,厚度为0.8 mm的薄板RD方向的强度达到最大值,抗拉强度为782 MPa,屈服强度为649 MPa;在变形温度为500℃时,厚度为2.0 mm的薄板TD方向的塑性达到最大值,其断后伸长率为29%。

TC4 titanium alloy thin sheets with two different specifications were produced by cladding-rolling process,and their microstructure and mechanical properties were studied by optical microscope,XRD diffractometer,room temperature tensile test and high temperature tensile test.The results show that the metallographic structure of the thin sheet after rolling and annealing is composed ofαphase and residualβphase,there is no obviousβtransformation structure in the structure,the morphology ofαphase presents linear,equiaxed and blocky,and there is residualβphase betweenαphases.The diffraction peaks ofαphase at different angles in the XRD patterns of the two specification of thin sheet are stronger than those ofβphase,and the diffraction peaks of the(102)and(200)crystal plane indexes for the thin sheet with a thickness of 0.8 mm are stronger.The room temperature strength of the thin sheet with a thickness of 0.8 mm is higher than that of the sheet plate with a thickness of 2.0 mm,the maximum tensile strength is 1077 MPa,and the maximum yield strength is 1029 MPa.The elongation after fracture of the two specifications of thin sheet are roughly the same,and the maximum value is 16.5%.The tensile strength of the thin sheet at 500℃is lower than that at 400℃.At the deformation temperature of 400℃,the strength in the RD direction of the thin sheet with a thickness of 0.8 mm reaches the maximum,the tensile strength is 782 MPa,and the yield strength is 649 MPa.When the deformation temperature is 500℃,the plasticity of the thin sheet with a thickness of 2.0 mm reaches the maximum in the TD direction,and its elongation after fracture is 29%.