不同离焦量对TC4钛合金半导体激光气体渗氮的影响
|
摘要
制造核电设备用钛合金需要进行激光气体渗氮,以提高钛合金表面硬度和耐磨性。离焦量是影响钛合金半导体激光气体渗氮的关键因素之一。保持其他工艺参数不变,分别采用5 mm、10 mm、15 mm和20 mm离焦量对TC4钛合金进行激光渗氮试验,分析渗氮层表面和横截面形貌,测量渗氮层硬度,拍摄渗氮层显微组织,对渗氮试样和TC4基体进行对比摩擦试验。结果表明,半导体激光器可对TC4钛合金表面渗氮,随着离焦量的增大,渗氮层尺寸减小,硬度降低,综合性能呈下降趋势。在本试验条件下,采用5 mm离焦量的激光气体渗氮层综合性能最优,其最大渗氮层厚度610μm,呈TiN特有的金黄色,渗氮层表面最大硬度可达982 HV,与TC4基材的350 HV硬度相比有较大提高,同等条件的耐磨试验使渗氮试样质量损失0.2 mg,使TC4基材质量损失1.78 mg。
Laser nitriding is needed to improve the surface hardness and wear resistance of titanium alloys for nuclear power equipment.There are many procedure factors affecting the semiconductor laser nitriding of titanium alloys,defocus distance is one of the key factors. The effect of defocus distance on the semiconductor laser nitriding of TC4 titanium alloy is studied. Other procedure parameters remain unchanged,the laser nitriding tests of TC4 titanium alloy is carried out by using 5 mm,10 mm,15 mm and 20 mm defocus distance respectively,the surface and cross-section appearance of nitriding layer are analyzed,the hardness of nitriding layer is measured,the microstructure of nitriding ed layer is photographed,the contrast friction test of nitriding sample and TC4 matrix is conducted. The results show that semiconductor laser can nitride on the surface of TC4 titanium alloy,when the defocus distance increases,the size and hardness of nitriding layer decrease,and the comprehensive performance deteriorate. Under the experimental condition of this study,the comprehensive performance of laser nitriding layer by 5 mm defocus distance is optimal,its maximum nitriding layer thickness is 610 μm,the nitriding layer has the characteristic golden color of TiN,the maximum surface hardness of nitriding layer can reach 982 HV,which is significantly higher than of TC4 substrate(350 HV),the wear test under the same conditions results in a mass loss of 0.2 mg for the nitriding sample and 1.78 mg for the TC4 substrate.
Laser nitriding is needed to improve the surface hardness and wear resistance of titanium alloys for nuclear power equipment.There are many procedure factors affecting the semiconductor laser nitriding of titanium alloys,defocus distance is one of the key factors. The effect of defocus distance on the semiconductor laser nitriding of TC4 titanium alloy is studied. Other procedure parameters remain unchanged,the laser nitriding tests of TC4 titanium alloy is carried out by using 5 mm,10 mm,15 mm and 20 mm defocus distance respectively,the surface and cross-section appearance of nitriding layer are analyzed,the hardness of nitriding layer is measured,the microstructure of nitriding ed layer is photographed,the contrast friction test of nitriding sample and TC4 matrix is conducted. The results show that semiconductor laser can nitride on the surface of TC4 titanium alloy,when the defocus distance increases,the size and hardness of nitriding layer decrease,and the comprehensive performance deteriorate. Under the experimental condition of this study,the comprehensive performance of laser nitriding layer by 5 mm defocus distance is optimal,its maximum nitriding layer thickness is 610 μm,the nitriding layer has the characteristic golden color of TiN,the maximum surface hardness of nitriding layer can reach 982 HV,which is significantly higher than of TC4 substrate(350 HV),the wear test under the same conditions results in a mass loss of 0.2 mg for the nitriding sample and 1.78 mg for the TC4 substrate.
引文
[1]张金东,吴崇志,郭倩,等.某新型核电站核岛建造过程的金属材料代换实践与分析[J].电焊机,2018,48(11):68-70.
[2]Dong H.Tribological properties of titanium-based alloys[J].Surface Engineering of Light Alloys,2010(3):58-80.
[3]Torrent F,Lavisse L,Berger P,et al.Influence of the composition of titanium oxynitride layers on the fretting behavior offunctionalizedtitanium substrates:PVDfilmsversus surface lasertreatments[J].Surface&CoatingsTechnology,2014(255):146-152.
[4]Sarma B,Ravi K S.Recent advances in surface hardening of titanium[J].The Minerals Metals Materials Journals,2011,63(2):85-92.
[5]Swarnima Singh,S.K.Tiwari,Raghuvir Singh.Influence of Laser Scanning Speed on Nitrided Ti6Al4V Surface[J].Surface Engineering,2017(8):1-9
[6]Duraiselvam M,Shariff S M,Padmanabham G,et al.Laser surface nitrided Ti-6Al-4V for light weight automobile disk brake rotor application[J].Wear,2013,309(1-2):269-274.
[7]Lisiecki A,Piwnik J.Tribological characteristic of titanium alloy surface layers produced by diode laser gas nitriding[J].Archives of Metallurgy and Materials,2016,61(2):543-552.
[8]李旭宾,石玗,朱明.半导体激光熔覆Ni60粉末的熔覆层成形机理分析[J].电焊机,2018,48(06):24-28.
[9]Kamat A M,Copley S M,Todd J A.Effect of processing parameters on microstructure duringlaser-sustainedplasma(LSP)nitriding of commercially-pure titanium[J].Journal of Applied Physics,2016(107):72-82.
[10]Conrad,H.Effect of interstitial solutes on the strength and ductility of titanium[J].Progress in Materials Science,1981,26(2-4):123-403.
[11]卢芳,王维夫,姚建华,等.不同氮氩比对TC4合金激光气体渗氮的影响[J].材料热处理学报,2011,32(S1):154-157.
[12]Kamat A M,Segall A E,Copley S M,et al.Enhancement of CP-titanum wear resistance using a two-step CO2lasersustained plasma nitriding process[J].Surface and Coatings Technology,2017(325):229-238.
[2]Dong H.Tribological properties of titanium-based alloys[J].Surface Engineering of Light Alloys,2010(3):58-80.
[3]Torrent F,Lavisse L,Berger P,et al.Influence of the composition of titanium oxynitride layers on the fretting behavior offunctionalizedtitanium substrates:PVDfilmsversus surface lasertreatments[J].Surface&CoatingsTechnology,2014(255):146-152.
[4]Sarma B,Ravi K S.Recent advances in surface hardening of titanium[J].The Minerals Metals Materials Journals,2011,63(2):85-92.
[5]Swarnima Singh,S.K.Tiwari,Raghuvir Singh.Influence of Laser Scanning Speed on Nitrided Ti6Al4V Surface[J].Surface Engineering,2017(8):1-9
[6]Duraiselvam M,Shariff S M,Padmanabham G,et al.Laser surface nitrided Ti-6Al-4V for light weight automobile disk brake rotor application[J].Wear,2013,309(1-2):269-274.
[7]Lisiecki A,Piwnik J.Tribological characteristic of titanium alloy surface layers produced by diode laser gas nitriding[J].Archives of Metallurgy and Materials,2016,61(2):543-552.
[8]李旭宾,石玗,朱明.半导体激光熔覆Ni60粉末的熔覆层成形机理分析[J].电焊机,2018,48(06):24-28.
[9]Kamat A M,Copley S M,Todd J A.Effect of processing parameters on microstructure duringlaser-sustainedplasma(LSP)nitriding of commercially-pure titanium[J].Journal of Applied Physics,2016(107):72-82.
[10]Conrad,H.Effect of interstitial solutes on the strength and ductility of titanium[J].Progress in Materials Science,1981,26(2-4):123-403.
[11]卢芳,王维夫,姚建华,等.不同氮氩比对TC4合金激光气体渗氮的影响[J].材料热处理学报,2011,32(S1):154-157.
[12]Kamat A M,Segall A E,Copley S M,et al.Enhancement of CP-titanum wear resistance using a two-step CO2lasersustained plasma nitriding process[J].Surface and Coatings Technology,2017(325):229-238.