Micro-morphology and mechanical properties of carbon nanotubes-Ti3AlC2/AZ91D composites
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摘要: 采用化学镀铜的方法对增强相碳纳米管(CNTs)和Ti3AlC2进行表面改性,热压烧结制备了CNTs-Ti3AlC2/AZ91D复合材料,研究了其微观组织和力学性能的变化及增强机制。结果表明:CNTs-Ti3AlC2/AZ91D复合材料内部主要物相为CNTs、Ti3AlC2、Mg和Al12Mg17,增强相均匀分布在基体内,在增强相与基体的界面处存在U相(MgAlCu),使二者界面结合良好。当增强相CNTs 和Ti3AlC2含量分别为1wt%和25wt%时,较镁合金AZ91D,CNTs-Ti3AlC2/AZ91D复合材料的弹性模量、拉伸强度、屈服强度和延伸率分别提高了120.30%、25.72%、126.50%和36.84%,弯曲强度和压缩强度分别为337.92 MPa和436.27 MPa。CNTs-Ti3AlC2/AZ91D复合材料的断裂方式表现为脆性断裂,其强化机制主要为热配错强化、Orowan强化和细晶强化机制。Abstract: Carbon nanotubes(CNTs) and Ti3AlC2 reinforced phase was surface modified by electroless copper plating. The CNTs-Ti3AlC2/AZ91D composites was prepared by hot pressing (HP) sintering. The microstructure, mechanical properties and strengthening mechanism of the CNTs-Ti3AlC2/AZ91D composites were studied.The results indicate that the main physical phases in the CNTs-Ti3AlC2/AZ91D composite are CNTs, Ti3AlC2, Mg and Al12Mg17, and the reinforced phase is uniformly distributed in the matrix. There is a U phase (MgAlCu) at the interface between the reinforced phase and the matrix, which can make the interface of the two well combined. When the reinforced phase content is CNTs (1wt%) and Ti3AlC2 (25wt%), compared with magnesium alloyAZ91D, the elasticity modulus, tensile strength, yield strength and elongation of the CNTs-Ti3AlC2/AZ91D composites are increased by 120.30%, 25.72%, 126.50% and 36.84%, respectively, and the flexural strength and compression strength are 337.92 MPa and 436.27 MPa. The fracture mode of the CNTs-Ti3AlC2/AZ91D composites is brittle fracture, and the strengthening mechanism is mainly thermal mismatch strengthening, Orowan strengthening and fine grain strengthening.
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Key words:
- hot pressing sintering /
- Ti3AlC2 /
- carbon nanotubes(CNTs) /
- copper plating /
- mechanical property /
- magnesium alloy
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表 1 碳纳米管(CNTs)和Ti3AlC2的特征参数
Table 1. Characteristic parameters of carbon nanotubes(CNTs) and Ti3AlC2
Material Density ρ/(g·cm–3) UBS/MPa UCS/MPa CTE/10−6 K−1 Purity CNTs 2.10 14×103 − 1.5 >98% Ti3AlC2 4.10 432±12 1 037±21 10.757 98.18% Notes: UCS—Ultimate compress strength; UBS—Ultimate flexural strength; CTE—Coefficient of thermal expansion. 表 2 CNTs-Ti3AlC2/AZ91D 复合材料的原料配比
Table 2. Raw material mass fraction of CNTs-Ti3AlC2/AZ91D composite
Number Mass fraction/wt% CNTs Ti3AlC2 AZ91D 1 0 0 Margin 2 0 25 75 3 1 25 74 Note: CNTs and Ti3AlC2 were copper plated. 表 3 CNTs-Ti3AlC2/AZ91D复合材料力学性能
Table 3. Mechanical properties of CNTs-Ti3AlC2/AZ91D composites
Material E/GPa 0.2%YS/MPa UTS/MPa Elongtion/% UCS/MPa UBS/MPa Ref. AZ91D 43.00 72.00 143.00 0.95 − − This work Ti3AlC2/AZ91D 98.45 − 94.00 0.17 365.22 182.02 This work CNTs-Ti3AlC2/AZ91D 94.74 163.07 179.78 1.30 436.27 337.92 This work TiC(5wt%)-Mg 42.00 123.00 − − 337.00 − [10] SiC(15wt%)/AZ91D 65.00 125.00 227.00 1.24 − − [11] Ti2AlC(10wt%)/AZ91D 56.00 135.00 215.00 1.90 382.00 − [7] CNTs(1.5wt%)/AZ91D 64.30 104.00 157.00 1.28 − − [5] Notes: E—Elastic modulus; UTS and 0.2%YS—Tensile strength and tensile yield strength, respectively. -
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