内生相非晶复合材料制备与力学性能研究
发布时间：2018-07-17 14:54
【摘要】：本文在优化成分和调整工艺的基础上,通过铜模喷铸法制备内生相非晶复合材料,通过XRD分析,组织观察,DSC热分析以及TEM透射来分析内生相非晶复合材料的物相组成、两相结构和成分;采用INSTRON5985型电子万能试验机以及分离式Hopkinson压杆测试材料在不同应变率以及不同直径尺寸下的力学性能表现,结合SEM扫描电镜观察材料的断口形貌,以揭示内生相非晶复合材料的变形机理。Ti48Zr20Nb12Cu5Be15内生相非晶复合材料由非晶基体相和均匀分布在非晶基体上的β-Ti(Zr,Nb)晶态相组成,在准静态和动态压缩条件下均表现有明显的应变率硬化效应,在准静态压缩条件下试样的抗压强度和断裂应变在1780MPa和27%以上,试样断口上有大量的脉状花样,随着应变率的提高,大量剪切滑移台阶以及协调变形的出现是其抗压强度和断裂应变增大的主要原因;动态压缩条件下试样的抗压强度和断裂应变在1556MPa和16%以上,大面积的合金熔覆、合金碎化以及高应变率剪切带运动与变形速度的不匹配导致材料在动态加载条件下较准静态条件下具有较低的强度和塑性;不同直径试样的准静态压缩测试表明该材料具有明显的尺寸效应,随着试样直径的减小,试样的抗压强度和断裂应变不断增大,大量分布的剪切带以及枝晶相的错动是使小尺寸试样具有高强度和塑性的主要原因。对不同Ag添加量的(Ti48Zr20Nb12Cu5Be15)100-xAgx内生相非晶复合材料进行研究表明:Ag的添加能够提高非晶形成能力,改变内生相的形态、尺寸和成分,随着Ag添加量的增加,内生枝晶相的枝晶尺寸和体积分数减小。(Ti48Zr20Nb12Cu5Be15)97.5Ag2.5内生相非晶复合材料在准静态以及动态压缩条件下具有比Ti48Zr20Nb12Cu5Be15内生相非晶复合材料更高的力学性能,其中准静态压缩抗压强度有18%-19.7%的提高,断裂应变有16.5%-21.2%的增加;动态压缩条件下材料的强度和断裂应变也有很大幅度的提高。两种成分的拉伸实验表明:实验过程中两种成分的试样均出现了颈缩现象,与Ti48Zr20Nb12Cu5Be15内生相非晶复合材料微观形貌相比,(Ti48Zr20Nb12Cu5Be15)97.5Ag2.5内生相非晶复合材料拉伸断口上纤维区和剪切唇区域的面积更大,纤维区韧窝的大小更加均一,并且韧窝的深度更大,因此后者具有更大的断裂变形和断后伸长率。对于内生相非晶复合材料,内生相的体积分数,尺寸以及形态分布对材料的性能有重要的影响,只有含有最优体积分数和尺寸分布配比的内生枝晶相时,材料在受力时能够产生足够的剪切带,并且剪切带在运动中得到枝晶相的阻碍,才会增加材料的强度和塑性。在(Ti48Zr20Nb12Cu5Be15)97.5Ag2.5内生相非晶复合材料中,枝晶相的体积分数和尺寸分别为78%和30um,均小于Ti48Zr20Nb12Cu5Be15内生相非晶复合材料中85%和50um的体积分数和尺寸,过大的枝晶相体积分数以及熟化的枝晶相分布使得内生相非晶复合材料中的枝晶相对剪切带的形核数量以及对剪切带扩展的阻碍作用没有(Ti48Zr20Nb12Cu5Be15)97.5Ag2.5内生相非晶复合材料中枝晶相的贡献大,因此(Ti48Zr20Nb12Cu5Be15)97.5Ag2.内生相非晶复合材料在不同应变率以及拉伸条件下的力学性能均优于Ti48Zr20Nb12Cu5Be15内生相非晶复合材料。
[Abstract]:In this paper, on the basis of optimizing the composition and adjusting process, the amorphous composite was prepared by the copper mold casting method. The phase composition, two phase structure and composition of the endophytic amorphous composites were analyzed by XRD analysis, microstructure observation, DSC thermal analysis and TEM transmission. The INSTRON5985 type electronic universal testing machine and the separated Hopkinson were used. The mechanical properties of the material under different strain rates and different diameters were measured by the pressure bar, and the fracture morphology of the material was observed by SEM scanning electron microscope to reveal the deformation mechanism of the endophytic Amorphous Composites. The.Ti48Zr20Nb12Cu5Be15 endogenic amorphous matrix and the beta -Ti (Zr, Nb) distributed evenly on the amorphous matrix. Under the conditions of quasi-static and dynamic compression, the strain rate hardening effect is obvious. Under quasi static compression conditions, the compressive strength and the fracture strain are above 1780MPa and 27%. There are a large number of pulse patterns on the fracture surface of the sample. With the increase of strain rate, a large number of shear slip steps and the occurrence of coordinated deformation appear. It is the main reason for the increase of the compressive strength and fracture strain; the compressive strength and the fracture strain of the specimen under dynamic compression are more than 1556MPa and 16%, the large area alloy cladding, the alloy fragmentation and the mismatch between the movement and the deformation velocity of the high strain rate shear band lead to the material under the dynamic loading condition compared with the quasi static condition. Low strength and plasticity; the quasi-static compression test of specimens with different diameters shows that the material has obvious size effect. With the decrease of the diameter of the specimen, the compressive strength and fracture strain of the specimen are increasing. The main reason for the high strength and plasticity of small size specimen is that the bulk of the shear band and the dislocation of the dendrite phase are the main reason. The study on (Ti48Zr20Nb12Cu5Be15) 100-xAgx endophytic Amorphous Composites with the addition of Ag shows that the addition of Ag can improve the amorphous formation ability, change the morphology, size and composition of the endophytic phase, and decrease the dendrite size and volume fraction of the endogenous dendrite with the increase of Ag addition. (Ti48Zr20Nb12Cu5Be15) 97.5Ag2.5 endophytic amorphous The composites have higher mechanical properties than Ti48Zr20Nb12Cu5Be15 endogenetic Amorphous Composites under quasi static and dynamic compression conditions, in which the quasi-static compression compressive strength is increased by 18%-19.7%, and the fracture strain is increased by 16.5%-21.2%, and the strength and fracture strain of the materials are greatly improved under the dynamic compression condition. The tensile test of two components showed that the necking phenomenon occurred in all the two components in the experimental process. Compared with the micromorphology of the Ti48Zr20Nb12Cu5Be15 endogenic amorphous composite, the area of the fiber area and the shear lip area on the tensile fracture surface of the 97.5Ag2.5 endogenic amorphous composite was larger, and the dimple of the fiber region was larger. The smaller one is smaller, and the depth of the dimple is greater, so the latter has a larger fracture deformation and a postfracture elongation. For the endogenetic amorphous composite, the volume fraction, size and shape distribution of the endophytic phase have an important influence on the properties of the material, only when the intrinsic dendrite contains the optimal body integral number and the size distribution ratio. A sufficient shear band can be produced when the force is subjected to force, and the shear band is hindered by the dendrite phase in motion. The strength and plasticity of the material will be increased. In (Ti48Zr20Nb12Cu5Be15) 97.5Ag2.5, the volume fraction and size of the dendrite phase are 78% and 30um, respectively, less than the amorphous Ti48Zr20Nb12Cu5Be15 in the endophytic phase. The volume fraction and size of 85% and 50um in the composite, the excessive dendrite volume fraction and the ripening dendrite phase distribution make the dendrite nucleation number of the dendrites in the amorphous composite material and the hindering effect on the shear band expansion without (Ti48Zr20Nb12Cu5Be15) 97.5Ag2.5 endogenic Amorphous Composites. As a result, the mechanical properties of (Ti48Zr20Nb12Cu5Be15) 97.5Ag2. endogenic Amorphous Composites under different strain rates and tensile conditions are superior to those of Ti48Zr20Nb12Cu5Be15 endogenic Amorphous Composites.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33
本文编号：2130001
[Abstract]:In this paper, on the basis of optimizing the composition and adjusting process, the amorphous composite was prepared by the copper mold casting method. The phase composition, two phase structure and composition of the endophytic amorphous composites were analyzed by XRD analysis, microstructure observation, DSC thermal analysis and TEM transmission. The INSTRON5985 type electronic universal testing machine and the separated Hopkinson were used. The mechanical properties of the material under different strain rates and different diameters were measured by the pressure bar, and the fracture morphology of the material was observed by SEM scanning electron microscope to reveal the deformation mechanism of the endophytic Amorphous Composites. The.Ti48Zr20Nb12Cu5Be15 endogenic amorphous matrix and the beta -Ti (Zr, Nb) distributed evenly on the amorphous matrix. Under the conditions of quasi-static and dynamic compression, the strain rate hardening effect is obvious. Under quasi static compression conditions, the compressive strength and the fracture strain are above 1780MPa and 27%. There are a large number of pulse patterns on the fracture surface of the sample. With the increase of strain rate, a large number of shear slip steps and the occurrence of coordinated deformation appear. It is the main reason for the increase of the compressive strength and fracture strain; the compressive strength and the fracture strain of the specimen under dynamic compression are more than 1556MPa and 16%, the large area alloy cladding, the alloy fragmentation and the mismatch between the movement and the deformation velocity of the high strain rate shear band lead to the material under the dynamic loading condition compared with the quasi static condition. Low strength and plasticity; the quasi-static compression test of specimens with different diameters shows that the material has obvious size effect. With the decrease of the diameter of the specimen, the compressive strength and fracture strain of the specimen are increasing. The main reason for the high strength and plasticity of small size specimen is that the bulk of the shear band and the dislocation of the dendrite phase are the main reason. The study on (Ti48Zr20Nb12Cu5Be15) 100-xAgx endophytic Amorphous Composites with the addition of Ag shows that the addition of Ag can improve the amorphous formation ability, change the morphology, size and composition of the endophytic phase, and decrease the dendrite size and volume fraction of the endogenous dendrite with the increase of Ag addition. (Ti48Zr20Nb12Cu5Be15) 97.5Ag2.5 endophytic amorphous The composites have higher mechanical properties than Ti48Zr20Nb12Cu5Be15 endogenetic Amorphous Composites under quasi static and dynamic compression conditions, in which the quasi-static compression compressive strength is increased by 18%-19.7%, and the fracture strain is increased by 16.5%-21.2%, and the strength and fracture strain of the materials are greatly improved under the dynamic compression condition. The tensile test of two components showed that the necking phenomenon occurred in all the two components in the experimental process. Compared with the micromorphology of the Ti48Zr20Nb12Cu5Be15 endogenic amorphous composite, the area of the fiber area and the shear lip area on the tensile fracture surface of the 97.5Ag2.5 endogenic amorphous composite was larger, and the dimple of the fiber region was larger. The smaller one is smaller, and the depth of the dimple is greater, so the latter has a larger fracture deformation and a postfracture elongation. For the endogenetic amorphous composite, the volume fraction, size and shape distribution of the endophytic phase have an important influence on the properties of the material, only when the intrinsic dendrite contains the optimal body integral number and the size distribution ratio. A sufficient shear band can be produced when the force is subjected to force, and the shear band is hindered by the dendrite phase in motion. The strength and plasticity of the material will be increased. In (Ti48Zr20Nb12Cu5Be15) 97.5Ag2.5, the volume fraction and size of the dendrite phase are 78% and 30um, respectively, less than the amorphous Ti48Zr20Nb12Cu5Be15 in the endophytic phase. The volume fraction and size of 85% and 50um in the composite, the excessive dendrite volume fraction and the ripening dendrite phase distribution make the dendrite nucleation number of the dendrites in the amorphous composite material and the hindering effect on the shear band expansion without (Ti48Zr20Nb12Cu5Be15) 97.5Ag2.5 endogenic Amorphous Composites. As a result, the mechanical properties of (Ti48Zr20Nb12Cu5Be15) 97.5Ag2. endogenic Amorphous Composites under different strain rates and tensile conditions are superior to those of Ti48Zr20Nb12Cu5Be15 endogenic Amorphous Composites.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33
【相似文献】
相关硕士学位论文 前2条
1 沈永华;内生相非晶复合材料制备与力学性能研究[D];北京理工大学;2015年
2 赵晓博;反相非水乳液法制备聚酰亚胺微球[D];太原理工大学;2010年
，本文编号：2130001
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/2130001.html
