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采用不同的改性剂对碳纤维进行了改性处理,制备了含碳纤维增强材料的SLS覆膜砂试样.通过对试样进行力学性能测试与SEM形貌分析,研究了碳纤维改性及其含量对SLS覆膜砂铸型抗拉和抗弯强度的影响.结果表明,经过浓硝酸与硅烷偶联剂KH550共同改性处理的碳纤维对SLS覆膜砂铸型的强化效果最佳,并随着改性碳纤维含量的增加,铸型强度先增大后减小.当改性碳纤维含量为3％时,SLS覆膜砂铸型后固化抗拉强度与抗弯强度均达到最大值,分别为6.385 MPa、8.011 MPa,比添加未改性碳纤维的铸型分别提升了46.18％、33.92％,较未添加碳纤维的铸型也分别提高了23.18％、31.46％.“,”With reinforced material of carbon fiber modified by different modifier,SLS coated sand specimens were prepared.The effects of carbon fiber modification and content on tensile strength and bending strength of the samples were analyzed by mechanical test and scanning electron microscopy (SEM).The results indicate that the modified carbon fibers treated by nitric acid and silane coupling agent (KH550) present the desirable reinforcement effect on SLS coated sand mold,and the strength of SLS coated sand mold is increased firstly and then decreased with the increase of carbon fiber content.When the carbon fiber content is 3 ％,the curing tensile strength and bending strength of the SLS coated sand mold reach maximum value of 6.385 MPa and 8.011 MPa,increased by 46.18％ and 33.92％ respectively,compared with those of one added unmodified carbon fibers,and increased by 23.18％ and 31.46％,respectively,compared with those of ones with absence of carbon fibers.