WC原料的多晶结构对合金组织及性能的影响
|
摘要
由于检测方法的限制,对WC粉体结构的研究和WC粉体结构对合金性能影响的研究在过去一段时间内多以"颗粒"作为其基本单元进行分析。本文采用EBSD技术,利用WC晶粒之间的取向差从多晶颗粒中分辨出WC单晶,实现了对多晶颗粒内部结构的检测,进一步研究了多晶结构对合金组织结构与性能的影响。研究结果表明,WC粉体中存在的大量多晶结构体,其在球磨过程中一部分会被破碎成粒径细小的单晶体,同时依然会有部分保留在混合料中。这些破碎后的细小颗粒会在后续的烧结过程中引起WC晶粒的异常长大,而在球磨态中残留的未破碎的多晶颗粒在后续的烧结中,则会引起WC团聚,增加了合金中WC/WC界面,引起合金断裂韧性K_(ⅠC)的下降。
Due to the limitations of the detection methods, the study of the WC powder structure and the effect of the WC powder structure on the properties of the alloy have been analyzed with "particles" as their basic unit in the past period of time. In this paper, by using the EBSD technique, the WC single crystal particles are distinguished from the polycrystalline particles by the difference in orientation between the WC grains, and the internal structure of the polycrystalline particles is detected. Based on this, the polycrystalline structure is further studied. Further more, the influence of polycrystalline structure on the microstructure and properties of the alloy is studied. The results show that a large number of polycrystalline structures present in the WC powder are partially broken into fine-grained single crystal particles in the ball milling process, and some of them remain in the mixture. These broken fine particles will cause abnormal growth of WC grains in the subsequent sintering process, while the unbroken polycrystalline particles remaining in the ball-milled state will cause WC agglomeration in the subsequent sintering process, which increasing the WC/WC interface in the alloy, causing the decrease of the K_(ⅠC) of the alloy.
Due to the limitations of the detection methods, the study of the WC powder structure and the effect of the WC powder structure on the properties of the alloy have been analyzed with "particles" as their basic unit in the past period of time. In this paper, by using the EBSD technique, the WC single crystal particles are distinguished from the polycrystalline particles by the difference in orientation between the WC grains, and the internal structure of the polycrystalline particles is detected. Based on this, the polycrystalline structure is further studied. Further more, the influence of polycrystalline structure on the microstructure and properties of the alloy is studied. The results show that a large number of polycrystalline structures present in the WC powder are partially broken into fine-grained single crystal particles in the ball milling process, and some of them remain in the mixture. These broken fine particles will cause abnormal growth of WC grains in the subsequent sintering process, while the unbroken polycrystalline particles remaining in the ball-milled state will cause WC agglomeration in the subsequent sintering process, which increasing the WC/WC interface in the alloy, causing the decrease of the K_(ⅠC) of the alloy.
引文
[1]张立,王元杰,余贤旺,王振波.WC粉末粒度与形貌对硬质合金中WC晶粒度、晶粒形貌与合金性能的影响[J].中国钨业,2008,23(4):23-26.Zhang Li,Wang Yuanjie,Yu Xianwang,WANG Zhenbo.Effect of particle size and morphology of tungsten carbide powder on grain size,grain morphology and properties of cemented carbide[J].China Tungsten Industry,2008,23(4):23-26.
[2]张卫兵.超细WC粉末Fsss粒度与超细硬质合金中WC晶粒度无法对应的原因分析[J].稀有金属与硬质合金,2013,41(6):51-54.Zhang Weibing.Analysis of the Causes for non-correspondence of fisher particle size of ultrafine WC powder to WC grain size of ultrafine cemented carbide[J].Rare Metals and Cemented Carbides,2013,41(6):51-54.
[3]尹超,张卫兵,谢晨辉,陆必志.原始WC粉末粒度组成对超细硬质合金组织及性能的影响[J].硬质合金,2017,34(1):7-13.Yin Chao,Zhang Weibing,Xie Chenhui,Lu Bizhi.Effect of particle size composition of original WC powder on microstructure and properties of ultra-fine cemented carbide[J].Cemented Carbide,2017,34(1):7-13.
[4]龙运兰,史顺亮,杨蓉.中颗粒钨粉高温碳化制取粗晶碳化钨粉的研制[J].硬质合金,2007,24(4):211-214.Long Yunlan,Shi Shunliang,Yang Rong.Manufacturing of coarse grain tungsten carbide powder by high temperature carbonization from medium grain tungsten powder[J].Cemented Carbide,2007,24(4):211-214.
[5]李园园,林江华,高跃红,等.硬质合金EBSD实验及结果评价方法[Z].第一次中国硬质合金学术会议论文,146-151.Li Yuanyuan,Lin Jianghua,Gao Yuehong,etc.Evaluation of EBSD experiment and result of cemented carbide[Z].The first Chinese cemented carbide academic conference paper,146-151.
[6]李园园,徐银超,林江华,等.EBSD在超细硬质合金WC晶粒尺寸统计中的应用[J].粉末冶金材料科学与工程,2015,20(2):162-167.Li Yuanyuan,Xu Yinchao,Lin jianghua,etc.Application of EBSDtechnology in superfine cemented carbide WC grain size statistic[J].Materials Science and Engineering of Powder Metallurgy,2015,20(2):162-167.
[7]于涛,贺鸣,罗学全,等.WC在湿磨中的分散与破碎过程研究[J].硬质合金,2017,34(3):155-166.Yu Tao,He Ming,Luo Xuequan,etc.Research on dispersion and breaking process during wet milling of WC[J].Cemented Carbide,2017,34(3):155-166.
[8]刘寿荣,刘宜.硬质合金断裂韧性评估[J].机械工程材料,1997,21(1):33-34.Liu Shourong,Liu Yi.Evaluation of fracture toughness of cemented Carbide[J].Materials For Mechanical Engineering,1997,21(1):33-34.
[9]果世驹.粉末烧结理论[M].北京:冶金工业出版社,1998:133-146.Guo Shiju.Powder sintering theory[M].Bei Jing:Metallurgical Industry Press,1998:133-146.
[10]Courtney T H.Microstructural evolution during liquid phase sintering:Part II.Microstructural coarsening[J].Metallurgical Transactions A.1977,8(5):685-689.
[11]Wang H,Fang ZZ,KS Hwang.Kinetics of initial coarsening during sintering of nanosized powders[J].Metallurgical&Materials Transactions A.2011,42(11):3534-3542.
[12]K arin Mannesson,Johan Jeppsson,Annika Borgenstam,John魡gren.Carbide grain growth in cemented carbides[J].Acta Materialia,2011,59(5):1912-1923.
[13]周新华,王力民.球磨时间对粗晶硬质合金性能的影响[J].硬质合金,2008,25(1):23-25.Zhou Xinhua,Wang Limin.Effect of milling time on performance of coarse-grained cemented carbide[J].Cemented Carbide,2008,25(1):23-25.
[14]张卫兵,颜练武,赵声志,杜承功.超细WC粉末微观缺陷的研究[J].硬质合金,2012,29(5):283-288.Zhang Weibing,Yan Lianwu,Zhao Shengzhi,Du Chenggong.Study on micro defects of ultrafine tungsten carbide powder[J].Cemented Carbide,2012,29(5):283-288.
[2]张卫兵.超细WC粉末Fsss粒度与超细硬质合金中WC晶粒度无法对应的原因分析[J].稀有金属与硬质合金,2013,41(6):51-54.Zhang Weibing.Analysis of the Causes for non-correspondence of fisher particle size of ultrafine WC powder to WC grain size of ultrafine cemented carbide[J].Rare Metals and Cemented Carbides,2013,41(6):51-54.
[3]尹超,张卫兵,谢晨辉,陆必志.原始WC粉末粒度组成对超细硬质合金组织及性能的影响[J].硬质合金,2017,34(1):7-13.Yin Chao,Zhang Weibing,Xie Chenhui,Lu Bizhi.Effect of particle size composition of original WC powder on microstructure and properties of ultra-fine cemented carbide[J].Cemented Carbide,2017,34(1):7-13.
[4]龙运兰,史顺亮,杨蓉.中颗粒钨粉高温碳化制取粗晶碳化钨粉的研制[J].硬质合金,2007,24(4):211-214.Long Yunlan,Shi Shunliang,Yang Rong.Manufacturing of coarse grain tungsten carbide powder by high temperature carbonization from medium grain tungsten powder[J].Cemented Carbide,2007,24(4):211-214.
[5]李园园,林江华,高跃红,等.硬质合金EBSD实验及结果评价方法[Z].第一次中国硬质合金学术会议论文,146-151.Li Yuanyuan,Lin Jianghua,Gao Yuehong,etc.Evaluation of EBSD experiment and result of cemented carbide[Z].The first Chinese cemented carbide academic conference paper,146-151.
[6]李园园,徐银超,林江华,等.EBSD在超细硬质合金WC晶粒尺寸统计中的应用[J].粉末冶金材料科学与工程,2015,20(2):162-167.Li Yuanyuan,Xu Yinchao,Lin jianghua,etc.Application of EBSDtechnology in superfine cemented carbide WC grain size statistic[J].Materials Science and Engineering of Powder Metallurgy,2015,20(2):162-167.
[7]于涛,贺鸣,罗学全,等.WC在湿磨中的分散与破碎过程研究[J].硬质合金,2017,34(3):155-166.Yu Tao,He Ming,Luo Xuequan,etc.Research on dispersion and breaking process during wet milling of WC[J].Cemented Carbide,2017,34(3):155-166.
[8]刘寿荣,刘宜.硬质合金断裂韧性评估[J].机械工程材料,1997,21(1):33-34.Liu Shourong,Liu Yi.Evaluation of fracture toughness of cemented Carbide[J].Materials For Mechanical Engineering,1997,21(1):33-34.
[9]果世驹.粉末烧结理论[M].北京:冶金工业出版社,1998:133-146.Guo Shiju.Powder sintering theory[M].Bei Jing:Metallurgical Industry Press,1998:133-146.
[10]Courtney T H.Microstructural evolution during liquid phase sintering:Part II.Microstructural coarsening[J].Metallurgical Transactions A.1977,8(5):685-689.
[11]Wang H,Fang ZZ,KS Hwang.Kinetics of initial coarsening during sintering of nanosized powders[J].Metallurgical&Materials Transactions A.2011,42(11):3534-3542.
[12]K arin Mannesson,Johan Jeppsson,Annika Borgenstam,John魡gren.Carbide grain growth in cemented carbides[J].Acta Materialia,2011,59(5):1912-1923.
[13]周新华,王力民.球磨时间对粗晶硬质合金性能的影响[J].硬质合金,2008,25(1):23-25.Zhou Xinhua,Wang Limin.Effect of milling time on performance of coarse-grained cemented carbide[J].Cemented Carbide,2008,25(1):23-25.
[14]张卫兵,颜练武,赵声志,杜承功.超细WC粉末微观缺陷的研究[J].硬质合金,2012,29(5):283-288.Zhang Weibing,Yan Lianwu,Zhao Shengzhi,Du Chenggong.Study on micro defects of ultrafine tungsten carbide powder[J].Cemented Carbide,2012,29(5):283-288.