层状陶瓷的制备、动态压缩性能及抗冲击机理

发布时间：2018-07-05 08:41

本文选题：反应热压烧结法 + 反应连接法　；参考：《西北工业大学》2016年博士论文

【摘要】：金属由于易加工、高塑性等优点被广泛用作装甲材料,但由于其低熔点、低硬度的特性使其在耐高温和防侵彻能力上远远难以满足抗高速高能冲击的需求。超硬陶瓷具有超高硬度、耐高温、不易变形等优点,被用作耐高速高能冲击材料,但陶瓷的脆性,使其对缺陷的容忍性极低,在高速高能冲击过程中极易失效,难以抵抗多次冲击。层状陶瓷材料由于具有高缺陷容忍性、高吸能能力以及结构可设计等优点,具有满足抗高速高能冲击要求的潜力。国内外研究重点主要集中在具有多孔界面或者低强度的弱界面等层状陶瓷方面的抗冲击性能,但由于界面强度低且界面结合强度低,在动态载荷作用下易因为界面破坏和脱粘而失效,限制了其结构完整性和能量吸收能力的提升。本文提出了反应热压烧结法(Reactive hot pressing,RHP)和反应连接法(Reactive jointing method,RJM)制备抗冲击层状陶瓷的新方法。对ZrO-Zr_2CN/Si_3N_4层状陶瓷进行了以下研究:优化了层状陶瓷的烧结工艺;研究了层状陶瓷结构控制的方法;研究了层状陶瓷结构与力学性能的关系;研究了层状陶瓷动态压缩性能的影响因素。研究了陶瓷层和金属层性质对M/C层状陶瓷的动态压缩性能的影响规律,对比了反应热压烧结法和反应连接法制备软硬交替叠层层状陶瓷的性能。主要研究内容如下:(1)研究了烧结温度和烧结压力对ZrO-Zr_2CN/Si_3N_4层状陶瓷的微结构和力学性能的影响。提高烧结温度和烧结压力,ZrO-Zr_2CN层和Si_3N_4层的致密度和硬度提高,层状陶瓷的弯曲强度和杨氏模量也提高。(2)研究了Si_3N_4层厚度和升温速率对ZrO-Zr_2CN/Si_3N_4层状陶瓷界面性质和微结构的影响,建立界面和层内反应模型。随着Si_3N_4层厚度或者升温速率的增加,界面强度增加(弱界面厚度减小或者转化为强界面);升温速率由10 oC/min变为17 oC/min时,ZrO-Zr_2CN层内的连续相由Zr_2CN相转变为ZrO与ZrO2的混合相(Zr-O混合相)。(3)研究了层结构和界面性质对ZrO-Zr_2CN/Si_3N_4层状陶瓷力学性能的影响。弱Zr_2CN界面厚度大于15μm,界面厚度是层状陶瓷强度的主要控制因素;弱界面厚度小于15μm时,减小界面厚度有助于提高层状陶瓷强度和断裂功,且弱界面转换为强界面时有利于提高层状陶瓷的弯曲强度和断裂功。较弱的ZrO-Zr_2CN软层降低了层状陶瓷的杨氏模量,但有利于提高层状陶瓷的断裂功。(4)研究了层间残余应力对ZrO-Zr_2CN/Si_3N_4层状陶瓷的能量吸收能力的影响。残余应力是影响能量吸收、释放和再分布的主要因素之一,随着Si_3N_4层内残余压应力的增加,层状陶瓷的弯曲断裂功增加。(5)研究了应变率对ZrO-Zr_2CN/Si_3N_4层状陶瓷的动态压缩性能的影响。随着应变率从1.1×103 s-1增加到3.3×103 s-1,ZrO-Zr_2CN/Si_3N_4层状陶瓷的动态应变增加;在应变率为2.0×103 s-1时,动态压缩强度取得最大值。裂纹萌生区域为Zr_2CN界面层,且随着应变率的增加,裂纹萌生区域的数量增加。(6)研究了界面性质和层结构对ZrO-Zr_2CN/Si_3N_4层状陶瓷的动态压缩性能的影响,建立动态失效模型。Zr_2CN界面厚度由3~5μm增加为25-30μm时,冲击应力波ZrO-Zr_2CN/Si_3N_4层状陶瓷的传播模型由三杆共轴碰撞模型变为四杆共轴碰撞模型。随着界面强度的增加,ZrO-Zr_2CN/Si_3N_4层状陶瓷的动态压缩强度和动态能量吸收能力提高,但动态假塑性变形能力降低;随着Si_3N_4层厚度的增加,层状陶瓷的动态压缩强度和动态应变增加,但动态能量吸收能力降低。(7)研究了陶瓷层厚度、陶瓷层种类和金属层种类对M/C层状陶瓷动态压缩性能的影响。增加陶瓷层厚度和金属层强度,提高了M/C层状陶瓷的动态压缩强度,但减弱了动态变形能力和能量吸收能力;增加陶瓷层强度,大幅度提高了层状陶瓷的动态变形能力和能力吸收能力;提高金属层强度,提高了M/C层状陶瓷的动态承载能力,但降低了层状陶瓷的动态变形能力。(8)对比了反应热压烧结法和反应连接法两种制备的软硬交替叠层层状陶瓷,为抗冲击软硬交替叠层层状陶瓷的合理应用建立依据。反应连接法具有周期短、温度低的优势,制备的M/C层状陶瓷适宜用于抵抗低能量的动态载荷;反应热压烧结法制备的ZrO-Zr_2CN/Si_3N_4层状陶瓷具有高强度、高应变和强能量吸收能力,更适宜于用于制备抗高速高能冲击的层状陶瓷。
[Abstract]:Metal is widely used as armored material because of its advantages of easy processing and high plasticity. However, due to its low melting point and low hardness, it is very difficult to meet the demand for high speed and high energy impact on high temperature resistance and penetration resistance. Super hard ceramics have the advantages of super hardness, high temperature resistance and non deformation, which are used as high speed and high energy impact materials, but they are used as high speed and high energy impact materials. The brittleness of ceramics is very low in tolerance to defects. It is very easy to fail in the process of high speed and high energy impact, and it is difficult to resist multiple shocks. The layered ceramic material has the advantages of high tolerance, high energy absorption capacity and structure design. It has the potential to meet the requirements of high speed and high energy impact. Due to low interfacial strength and low interfacial bonding strength, the interfacial failure and debonding are easy to fail due to the low interfacial strength and low interfacial bonding strength, which has limited the structural integrity and energy absorption ability. This paper proposed a reaction hot pressing sintering (Reacti) method. Ve hot pressing, RHP) and the reaction connection method (Reactive jointing method, RJM) are used to prepare a new method for the preparation of impact resistant layered ceramics. The following studies are made on the ZrO-Zr_2CN/Si_3N_4 layered ceramics: the sintering process of layered ceramics is optimized, the formula for controlling the structure of layered ceramics is studied, and the relationship between the structure of layered ceramics and the mechanical properties is studied. The influence factors of dynamic compression properties of layered ceramics were investigated. The effects of the properties of ceramic layer and metal layer on the dynamic compression properties of M/C layered ceramics were studied. The properties of soft hard alternating laminated ceramics were compared with the reaction hot pressing and reaction connection methods. The main contents are as follows: (1) the sintering temperature and pressure are studied. The influence of force on the microstructure and mechanical properties of ZrO-Zr_2CN/Si_3N_4 layered ceramics. Increase the sintering temperature and sintering pressure, increase the density and hardness of the ZrO-Zr_2CN layer and Si_3N_4 layer, and improve the bending strength and Young's modulus of the layered ceramics. (2) the interfacial properties of ZrO-Zr_2CN/Si_3N_4 layered ceramics are studied by the thickness of Si_3N_4 layer and the rate of rising temperature. As the thickness of the Si_3N_4 layer or the heating rate increases, the interface strength increases with the increase of the thickness of the Si_3N_4 layer (the thickness of the weak interface or the strong interface); when the heating rate changes from 10 oC/min to 17 oC/min, the continuous phase in the ZrO-Zr_2CN layer is transformed from Zr_2CN phase to the mixture of ZrO and ZrO2 (Zr-O mixed). (3) (3) the effect of layer structure and interfacial properties on the mechanical properties of layered ceramics is studied. The thickness of the weak Zr_2CN interface is more than 15 mu m, and the thickness of the interface is the main controlling factor of the strength of layered ceramics. When the thickness of the weak interface is less than 15 u m, the decrease of the thickness of the interface is helpful to improve the strength and fracture work of the layered ceramics and the weak interface transition. The weak ZrO-Zr_2CN soft layer reduces the young's modulus of layered ceramics, but is beneficial to improve the fracture work of layered ceramics. (4) the influence of interlayer residual stress on the energy absorption capacity of ZrO-Zr_2CN/Si_3N_4 layered ceramics is studied. Residual stress is the influence of energy absorption. One of the main factors of collecting, releasing and redistributing, with the increase of residual compressive stress in the Si_3N_4 layer, the flexural fracture work of layered ceramics is increased. (5) the effect of strain rate on the dynamic compression properties of ZrO-Zr_2CN/Si_3N_4 layered ceramics is studied. With the strain rate increasing from 1.1 x 103 S-1 to 3.3 x 103 s-1, the movement of ZrO-Zr_2CN/Si_3N_4 layered ceramics The dynamic compressive strength is maximum when the strain rate is 2 x 103 s-1. The crack initiation area is Zr_2CN interface layer, and the number of crack initiation area increases with the increase of strain rate. (6) the dynamic failure of ZrO-Zr_2CN/Si_3N_4 layered ceramics is studied by the interfacial properties and layer structure. When the interface thickness of the model.Zr_2CN is increased from 3~5 to 25-30 m, the propagation model of the impact stress wave ZrO-Zr_2CN/Si_3N_4 layer ceramics is transformed from the three bar coaxial collision model to the four bar coaxial collision model. With the increase of the interface strength, the dynamic compression strength and dynamic energy absorption capacity of the ZrO-Zr_2CN/Si_3N_4 layered ceramics are improved, but the dynamic false is false. The dynamic compressive strength and dynamic strain increased with the increase of the thickness of Si_3N_4 layer, but the dynamic energy absorption capacity decreased. (7) the influence of ceramic layer thickness, ceramic layer and metal layer on the dynamic compression properties of M/C layered ceramics was studied. The thickness of ceramic layer and the strength of metal layer were increased. The dynamic compressive strength of M/C layered ceramics was reduced, but the dynamic deformation ability and energy absorption capacity were weakened, and the dynamic deformation ability and ability absorption capacity of the ceramic layer were increased greatly, the strength of the metal layer and the dynamic bearing capacity of the M/C layered ceramics were improved, but the dynamic deformation energy of the layered ceramics was reduced. (8) a comparison of two soft hard laminated laminated ceramics prepared by reactive hot press sintering and reaction connection method, which is the basis for the rational application of the laminated ceramic with shock resistant soft and hard alternating layers. The reaction connection method has the advantages of short period and low temperature. The prepared M/C layered ceramics are suitable for resisting low energy dynamic load and reaction heat. The ZrO-Zr_2CN/Si_3N_4 layered ceramics prepared by the pressure sintering method have high strength, high strain and strong energy absorption ability, which is more suitable for the preparation of layered ceramics with high speed and high energy impact.
【学位授予单位】：西北工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ174.1

【参考文献】