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为了考察挤压态复合材料的性能,挤压铸造SiCw/1050A复合材料被热挤压,对复合材料中的组织结构参数进行了测定和分析,并采用混合法则对挤压态SiCw/1050A复合材料的强度进行了预测,结果表明,挤压导致复合材料中组织参数发生变化(包括晶须和基体),进而影响复合材料的性能,用修正的混合定律预测挤压态SiCw/1050A复合材料纵向强度时必须增大表征基体贡献的系数c到6左右才能得到满意的结果,表明基体强度是影响SiCw/1050A复合材料强度的一个重要因素。 相似文献
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SiCw/MB15镁基复合材料挤压板材的力学性能和断口分析 总被引:1,自引:0,他引:1
研究了SiCw/MB15镁基复合材料板材的力学性能和拉伸断口,研究结果表明,SeCw/MB15镁基复合材料板材中晶须轴向平行于挤压方向排布,分布均匀,与基体合金的结合良好,晶须排布的方向性对SiCw/MB15镁基复合材料板材的弹性模量及延伸率几乎没有影响,但是SiCw/MB15镁基复合材料板材的抗拉强度表现出明显的方向性。 相似文献
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用挤压铸造法制备不同ZnO包覆量的硼酸镁晶须增强的6061铝基复合材料,并对其进行热挤压处理。对复合材料的显微组织及其力学性能进行研究。结果表明:随着ZnO包覆量的增大,铸态复合材料的弹性模量直线增加。铸态复合材料的极限抗拉强度和屈服强度随ZnO包覆量的增大先增大后减小。然而,铸态复合材料的伸长率基本一致。经挤压后,复合材料的伸长率大幅增加;无涂层复合材料的极限抗拉强度最大,且其弹性模量有所提高。涂覆ZnO涂层的复合材料中晶须发生明显的折断现象。但是,随着ZnO包覆量的增大,晶须的破坏程度有限。 相似文献
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热挤压工艺参数对挤压铸造SiCw/L3复合材料组织和性能的影响 总被引:5,自引:0,他引:5
研究了挤压比和挤压温度对挤压铸造SiCw/L3 复合材料组织和性能的影响。结果表明,当挤压温度升高时, 晶须沿挤压方向定向排列程度基本未变, 而晶须的折断程度则减弱, 导致复合材料的抗拉强度提高; 当挤压比增大时, 晶须沿挤压方向定向排列程度增大, 晶须的折断程度也增大, 这两个决定强度的相反过程造成了复合材料的抗拉强度在挤压比为18∶1 时出现最大值。用修正的混合法则预测挤压态复合材料强度时, 必须增大基体对强度贡献部分的系数c* 。 相似文献
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The load transfer mechanism and mechanical properties of SiC whisker reinforced aluminum matrix composites were investigated.
A generalized shear-lag model was proposed to analyze the effects of the aspect ratio, misorientation angle and volume fraction
of SiC whisker on the mechanical properties of SiCw/Al composites. A new concept on effective aspect ratio was suggested,
combining the effects of aspect ratio and alignment of whiskers, to calculate the effective stress acting on the aluminum
matrix in SiCw/Al composites. The magnitude and anisotropy of the yield strength of the SiCw/2124Al composite can be estimated
more accurately by substituting the average aspect ratio with the effective aspect ratio based on the generalized shear-lag
model. The SiCw/2124Al composite with the largest effective aspect ratio showed the lowest minimum creep rate which decreased
with increasing effective aspect ratio of SiC whisker, but were found to be almost similar under the same effective stress
acting on the Al matrix. It is suggested that the role of SiC whisker is to improve the mechanical properties by reducing
the effective stress acting on the Al matrix in the SiCw/Al metal matrix composite.
This article is based on a presentation made in the symposium “The 1st KIM-JIM Joint Symposium: High Strength Ratio Aluminum Alloys”, held at Inha University, Inchon, Korea, October 22. 1999 under
the auspices of The Korean Institute of Metals and Materials and The Japanese Institute of Metals. 相似文献
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对SiC2/Al2O3陶瓷的低粘度、高固相体积分数浓悬浮体的制备以及凝胶注模成型后坯体的性能和显微结构进行了研究,着重分析了长径比不同的2种SiC晶须及其添加量对坯体性能的影响.结果表明,坯体的相对密度、抗弯强度与SiC晶须的长径比和添加量有关,浆料的粘度随着晶须长径比和添加量的增大而增加.坯体的抗弯强度随着晶须添加量的增加呈现一种先上升后下降的趋势.凝胶注模成型后坯体结构均匀、致密,相对密度为60%,抗弯曲强度达38.5 MPa.通过显微结构观察,裂纹偏转、晶须拔出和晶须桥连是晶须增强的主要机制. 相似文献
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挤压铸造SiCw/L3复合材料液-固两相区包覆挤压 总被引:2,自引:0,他引:2
研究了SiCw/L3复合材料固相区和液固两相区挤压行为,提出了包覆挤压方法。通过SEM、图象分析和拉伸性能测试,对铸态和挤压态SiCw/L3复合材料的组织和性能进行了观察、分析和测定。结果表明,液固两相区挤压虽然有效地减轻了晶须折断程度,却造成了挤压棒表面质量的恶化;液固两相区包覆挤压既有效地减轻了晶须折断程度,又保证了挤压棒的表面质量。与固态挤压相比,液固两相区包覆挤压的挤压棒强度进一步提高和塑性大幅度下降,可归因于晶须折断程度减轻。 相似文献
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ZHANG Wenlong ZHANG Mu GU Mingyuan WANG Dezun and YAO Zhongkai) State Key Lab of MMCs Shanghai Jiaotong University Shanghai China) School of Materials Science Engineering Harbin Institute of Technology Harbin China 《稀有金属(英文版)》2003,22(4)
SiCw/Al composite was fabricated through a squeeze cast route and cold rolled to about 30%, 50% and 70% re-duction in thickness, respectively. The length of whiskers in the composite before and after rolling was examined using SEM. Some of the rolled composites were recrystallization annealed to remove the work hardening of matrix alloy. The tensile strength of the rolled and annealed SiCw/Al composites was examined and then associated with the change of the whisker length and the work hardening of matrix alloy. It was found that the tensile strength is a function of the degree of cold rolling. For the cold rolled composites, with the increase in the degree of cold rolling, the tensile strength increases at first, and decreases when the degree of cold rolling exceeds 50%. For the annealed ones, however, the tensile strength de-creases monotonously with the increase in rolling degree. The different changes in tensile strength between the rolled and annealed composites could be attributed to the result of 相似文献
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以三氯甲基硅烷(CH3SiCl3,MTS)为先驱体原料,采用化学气相沉积法在C/C复合材料基体上原位生长碳化硅晶须,研究稀释气体流量、催化剂以及沉积温度对碳化硅晶须生长的影响。结果表明:有催化剂存在时可以制备具有较高长径比的SiCw,无催化剂制备的SiC主要以短棒状或球状SiC为主;随着稀释气体流量或者沉积温度的增加,SiCw的产率是先增加、后减少,在1 100℃、载气和稀释气体流量均为100 mL/min时,制备的碳化硅晶须的产率最高,晶须质量最好。 相似文献
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研究了SiCW/Y-TZP/Al2O3系复合陶瓷的显微结构及其力学性能,通过透射电镜拉伸试样中的裂纹扩展形态与组织变化,分析了晶须与ZrO2相变增韧机制。结果表明,陶瓷体内各相结合致密,分布较为均匀,其室温强度和断裂韧度分别为1100MPa和11.9MPa.m^1/2,晶须拔出,裂纹偏转及ZrO2t-m相变是该复合材料的主要增韧机制。SiC晶须和Y-TZP的共同作用,对复合材料强度和断裂韧性的提高 相似文献
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热挤压对SiCw/MB15镁基复合材料组织和性能的影响 总被引:2,自引:0,他引:2
利用SEM,TEM,X射线衍射仪等方法,研究了挤压对SiCw/MB15镁基复合材料组织和性能的影响。结果表明:热挤压后复合材料组织更加均匀,SiC晶须长轴与挤压方向平行,晶须的增强作用得到了充分的发挥,显著提高了SiCw/MB15镁基复合材料的力学性能。 相似文献
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GUO Shuqi HAN Guihuan YAO Zhongkai Harbin Institute of Technologh Harbin China YAO Zhongkai Dept.of Metals Technology Harbin Institute of Technology Harbin China 《金属学报(英文版)》1989,2(9):189-194
This paper presents an investigation on the microstructures and properties of the17v.-% SiCw/Al-12Si composites.TEM observations and EDAX analysis revealed that Aldiffuses into the SiC whiskers and that dislocations exist at the whisker/matrix interfaces.Tensile test results showed that the isothermal exposure and thermal cycle at both 573K and733 K caused the UTS reduction of the composites,and the reduction in UTS due to thermalexposure at 733 K was much more significant than that due to thermal cycle at the same tem-perature.The SiC_W/Al-12Si composites were also found to have exellent wear resistance,which does not seem to vary much with the volume content of whiskers in the ronge of 11—17%. 相似文献
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SiC晶须增韧WC陶瓷刀具材料的研究 总被引:1,自引:0,他引:1
通过正交试验法对WC/SiCw陶瓷复合材料进行了成分和热压工艺参数优化,经优化制备的该类复合材料与纯WC材料相比,弯曲强度提高了约50%,断裂韧性提高了30% ̄40%,维氏硬度提高了10% ̄15%。切削试验表明,本试验制得的WC/SiCw复合陶瓷刀具材料的车削性能优于同类型硬质合金材料,表明通过SiCw替代金属粘结相来增韧补强WC陶瓷刀具材料的方法是可行的。 相似文献