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TiB2基陶瓷/42CrMo合金层状梯度材料力学测试与结构设计

TiB2-based ceramics/42CrMo alloy layered gradient material mechanical test and structure design

  • 摘要: 在以往超重力场合成梯度材料的基础上,制备出组分含量TiB2-TiC-Fe呈连续梯度变化的TiB2基陶瓷/42CrMo合金梯度材料. 对材料进行XRD,SEM,硬度测试以及三点弯曲强度测试,并采用电测法获取陶瓷基体部分的弹性模量,并在此基础上,对中间过渡区的弹性模量进行拟合,最后再采用解析方法计算梯度材料的应力应变分布. 结果表明,TiB2基陶瓷/42CrMo合金相界呈连续梯度变化,硬度自陶瓷顶部至合金底部呈梯度递减.三点弯曲测试发现TiB2基陶瓷/42CrMo合金材料具有类似于金属的塑性变形特征,从而出现明显的失效延迟行为. 采用电测法得出纯陶瓷组分的弹性模量约为560 GPa,参数拟合得出中间过渡区的弹性模量变化形式更趋近于三角函数,计算得出的应力表示自金属底部出现损伤,而后裂纹向陶瓷顶部方向扩展,与该材料试验现象契合.

     

    Abstract: Based on the previous supergravity field synthesis gradient materials, a TiB2-based ceramic /42CrMo graded material with continuous gradient content of TiB2-TiC-Fe has been preparatived. XRD, SEM, hardness test and three-point bending strength test on the materials are conducted. And electrical measuring method is used to obtain ceramic substrate part of elasticity modulus.The elastic modulus of the intermediate transition zone is fitted. Finally, an analytical method is used to calculate the stress-strain distribution of the graded material.The results show that the ceramic/alloy phase boundary changes in a continuous gradient, and the hardness decreases in a gradient from ceramic to metal. Three point bending test found that the type of material has similar to the metal plastic deformation features. Therefore, obvious failure delay behavior appears. The elastic modulus of pure ceramic is about 560 GPa. The variation form of elastic modulus in the intermediate transition zone is closer to trigonometric function. The calculated stress indicates that the damage occurs from the bottom of the metal, and then the crack spreads to the top of the ceramic, which is consistent with the experimental phenomenon of this type of material.

     

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