摘要
采用低压铸造工艺在715℃ 浇注了ZL114A异形结构导弹壳体,充型和凝固时长分别为4.79 s与1 615 s,实现了自上而下的平稳充型,形成了自上而下与自内向外的凝固顺序.结果表明,铸态组织主要由α-Al基体、α-Al+Si共晶体、Mg2Si相与Al3Ti相等组成,导弹壳体顶端、中部和底部区域平均晶粒直径分别为116.09、147.76与178.33 μm;试样抗拉强度、屈服强度、伸长率与弹性模量均值分别为344.66 MPa、275 MPa、8.44%和71.5 GPa,离散系数分别为0.55%、0.93%、3.5%与0.7%.沿导弹壳体高度方向自上而下本体试样力学性能连续下降,顶端区域抗拉强度、屈服强度、伸长率与弹性模量分别为364 MPa、284 MPa、9.2%与71.5 GPa;时效热处理保温后铸态板条状、块状Si相形貌转变为近球状,断口表面残留大量微观韧窝,断裂机制为典型的韧窝断裂.
Abstract
ZL114A heteromorphic missile shell was manufactured at 715℃ by low-pressure filling with filling and solidification time of 4.79 s and 1 615 s,achieving a smooth top-down filling with a top-down and inside-outside solidi-fication sequence.The results indicate that as-cast structure is mostly composed of α-Al matrix,α-Al+Si eutectic,Mg2Si phase,and Al3Ti phase,and average grain size of shell in the top,middle,and bottom regions are 116.09,147.76,and 178.33 μm,respectively.The mean values of tensile strength,yield strength,elongation and elasticity modulus are 344.66 MPa,275 MPa,8.44%,and 71.5 GPa,and dispersion coefficients are 0.55%,0.93%,3.5%and 0.7%,respectively.The mechanical properties are declined progressively from top to bottom along the height of the missile shell,and tensile strength,yield strength,elongation,and elasticity modulus in top region are 364 MPa,284 MPa,9.2%,and 71.5 GPa,respectively.The morphology of as-cast Si phase is transformed from slatted and blocky shape to a roughly spherical shape after aging heat treatment,with large amounts of residual dimples on the frac-ture surface,and fracture mechanism is characterized by dimple fracture.
NETL
NSTL
维普
万方数据