喷射沉积Al-7Si-0.5Cu-0.5Mg热变形行为研究
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摘要
亚共晶铝硅合金因具有轻质、耐腐蚀、高的比强度和优异力学性能等优点,被广泛应用于航空、航天、军事及汽车工业领域。利用喷射沉积技术制备亚共晶Al-7Si-0.5Cu-0.5Mg合金,通过高温压缩试验结合微观组织分析,研究温度和应变速率对沉积态亚共晶铝硅合金热变形行为的影响规律,最终确定沉积态合金优化的致密化工艺参数。研究发现,采用双曲线正弦函数建立的沉积态合金的本构方程,能够准确描述沉积态合金的流变行为。喷射沉积合金主要由Al相、Si相、Al_2Cu相和Mg_2Si相组成,硅相平均尺寸为8.5μm。当温度为300℃,随着应变速率由1s~(-1)减小至0.001s~(-1),合金的压缩应力由112.19 MPa减小至61.26 MPa。在应变速率为0.001s~(-1)下,随着变形温度由300℃升高至450℃,合金压缩流变应力由61.26 MPa减小至21.35 MPa。合金在低应变速率(0.001s~(-1))和相对较高的温度(450℃)下变形时,由于相对充足的变形时间和铝基体较高的软化程度,导致组织中硅相尺寸增大,不利于合金性能的提高。沉积态合金最佳的变形参数为变形温度400℃,应变速率0.01s~(-1)。
Hypoeutectic Al-Si alloy is widely used in aviation, aerospace, military and automobile industry because of its notable properties, such as light weight, good corrosion resistance, high specific strength and excellent mechanical properties. The spray deposition technology is used for the fabrication of hypoeutectic Al-7Si-0.5Cu-0.5Mg alloy. The hot deformation behavior of spray formed Al-7Si-0.5Cu-0.5Mg alloy is investigateded by high temperature compression tests as well as microstructural analysis. Results showed that the constitutive equation of Al-7 Si-0.5Cu-0.5Mg alloy is established by hyperbolic-sine equation, and the rheological behavior of the alloy is well demonstrated. The deposited alloy was composed of Al, Si, Al_2Cu and Mg_2Si phases. The average size of Si phase is around 8.5μm. As the strain rate reduced from 1s~(-1) to 0.001s~(-1), the compressive stress of the alloy decreased from 112.19MPa to 61.26MPa at the temperature of 300℃. With the deformation temperature increase from 300 ℃ to 450 ℃, the flow stress of the alloy reduce from 61.26 MPa to 21.35 MPa with the strain rate of 0.001s~(-1). An adequate deformation time and a high soften degree of Al matrix occurred when the alloy deforme at a low strain rate(0.001s~(-1)) and a relative high temperature(450 ℃). Accordingly, the alloy exhibited increased size of Si phase, which is negative for improving the mechanical properties of the alloy. The optimal deformation temperature and the strain rate are 400 ℃ and 0.01s~(-1), respectively.
Hypoeutectic Al-Si alloy is widely used in aviation, aerospace, military and automobile industry because of its notable properties, such as light weight, good corrosion resistance, high specific strength and excellent mechanical properties. The spray deposition technology is used for the fabrication of hypoeutectic Al-7Si-0.5Cu-0.5Mg alloy. The hot deformation behavior of spray formed Al-7Si-0.5Cu-0.5Mg alloy is investigateded by high temperature compression tests as well as microstructural analysis. Results showed that the constitutive equation of Al-7 Si-0.5Cu-0.5Mg alloy is established by hyperbolic-sine equation, and the rheological behavior of the alloy is well demonstrated. The deposited alloy was composed of Al, Si, Al_2Cu and Mg_2Si phases. The average size of Si phase is around 8.5μm. As the strain rate reduced from 1s~(-1) to 0.001s~(-1), the compressive stress of the alloy decreased from 112.19MPa to 61.26MPa at the temperature of 300℃. With the deformation temperature increase from 300 ℃ to 450 ℃, the flow stress of the alloy reduce from 61.26 MPa to 21.35 MPa with the strain rate of 0.001s~(-1). An adequate deformation time and a high soften degree of Al matrix occurred when the alloy deforme at a low strain rate(0.001s~(-1)) and a relative high temperature(450 ℃). Accordingly, the alloy exhibited increased size of Si phase, which is negative for improving the mechanical properties of the alloy. The optimal deformation temperature and the strain rate are 400 ℃ and 0.01s~(-1), respectively.
引文
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[23]CHEN G,KE Z H,REN C Z,et al.Constitutive modeling for Ti-6Al-4V alloy machining based on the SHPB tests and simulation[J].Journal of Mechanical Engineering,2016,29(5):962-970.
[2]KOBAYASHI T.Strength and fracture of aluminum alloys[J].Materials Science and Engineering A,2000,280(1):8-16.
[3]沈军,谢壮德,董寅生,等.快速凝固铝硅合金的性能、应用及发展方向[J].粉末冶金技术,2000,18(3):208-213.SHEN Jun,XIE Zhuangde,DONG Yansheng,et al.Properties,application and developing trend of rapidly solidified aluminum-silicon alloys[J].Powder Metallurgy Technology,2000,18(3):208-213.
[4]ZOU Y Z,XU Z B,HE J,et al.Crystallographic characteristic of intermetallic compounds in Al-Si-Mg casting Alloys using electron backscatter diffraction.Journal of Mechanical Engineering,2010,23(3):305-311.
[5]JIA Y D,CAO F Y,MA P,et al.Microstructure and thermal conductivity of hypereutectic Al-high Si produced by casting and spray deposition[J].Journal of Materials Research,2016,31(19):2948-2955.
[6]黎常浩,陈振华,陈鼎,等.喷射沉积Si Cp/Al-20Si复合材料高周疲劳行为研究[J].机械工程学报,2012,48(10):40-44.LI Changhao,CHEN Zhenhua,CHEN Ding,et al.Research on high-cycle fatigue behavior of spray deposited Si Cp/Al-20Si composite[J].Journal of Mechanical Engineering,2012,48(10):40-44.
[7]尤俊华,李想,马理.喷射成形Al-Zn-Mg-Cu合金回归再时效过程的XRD分析[J].机械工程学报,2016,52(18):44-50.YOU Junhua,LI Xiang,MA Li.XRD Study on retrogression and re-aging of spray formed Al-Zn-Mg-Cu alloy[J].Journal of Mechanical Engineering,2016,52(18):44-50.
[8]JIA Y D,CAO F Y,NING Z L,et al.Influence of second phases on mechanical properties of spray-deposited Al-Zn-Mg-Cu alloy[J].Materials Design,2012,40:536-540.
[9]霍光,匡星,况春江,等.喷射成形工艺的理论研究进展[J].粉末冶金技术,2008,26(5):382-389.HUO Guang,KUANG Xing,KUANG Chunjiang,et al.Theoretical models in spray forming[J].Powder Metallurgy Technology,2008,26(5):382-389.
[10]杨伏良,张伟,易丹青,等.快速凝固喷射沉积制备Al-40Si组织分析[J].粉末冶金技术,2006,24(3):166-169.YANG Fuliang,ZHANG Wei,YI Danqing,et al.Microstructure analysis of rapidly solidified Al-40Si alloy fabricated by spray deposition[J].Powder Metallurgy Technology,2006,24(3):166-169.
[11]苏睿明李荣德张震.喷射态7075合金回归再时效工艺研究[J].机械工程学报,2016,52(16):57-64.SU Ruiming,LI Rongde,ZHANG Zhen.Study on retrogression and re-aging of spray formed 7075 alloy[J].Journal of Mechanical Engineering,2016,52(16):57-64.
[12]JIN N P,ZHANG H,HAN Y,et al.Hot deformation behavior of 7150 aluminum alloy during compression at elevated temperature[J].Materials Characterization,2009,60:530-536.
[13]MEYERS MA,BENSON DJ,VOHRINGER O.Constitutive description of dynamic deformation:Physically-based mechanisms[J].Materials Science and Engineering A,2002,A322(1-2):194-216.
[14]LEE W,SUE W,LIN C,et al.The strain rate and temperature dependence of the dynamic impact properties of 7075 aluminum alloy[J].Journal of Materials Processing Technology,2000,100(1-3):116-122.
[15]康福伟.喷射成形GH742y合金热变形行为及时效特性[D].哈尔滨:哈尔滨工业大学,2007.KANG Fuwei.Hot deformation behavior and aging characteristics of spray formed GH742y alloy[D].Harbin:Harbin Institute of Technology,2007.
[16]JIN N,ZHANG H,HAN Y,et al.Hot deformation behavior of 7150Aluminum alloy during compression at elevated temperature[J].Materials Characterization,2009,60(6):530-536.
[17]凌闯,王敬丰,赵亮.高硅铝合金标准样品的热变形行为[J].中国有色金属学报,2010,20(5):833-839.LING Chuang,WANG Jingfeng,ZHAO Liang.Hot deformation behavior of high silicon aluminum alloy as standard sample[J].The Chinese Journal of Nonferrous Metals,2010,20(5):833-839.
[18]ZHANG W,LIU Y,LI HZ,et al.Constitutive modeling and processing map for elevated temperature flow behavior of a powder metallurgy titanium aluminide alloy[J].Journal of Material Processing Technology,2009,209:5363-5370.
[19]MANDAL S,RAKESH V,SIVAPRASAD P V,et al.Constitutive equations to predict high temperature flow stress in a Timodified austenitic stainless steel[J].Materials Science and Engineering A,2009,500:114-121.
[20]LIN Y C,CHEN M S,ZHONG J.Constitutive modeling for elevated temperature flow behavior of 42 Cr Mo steel[J].Computer Material Science,2008,42:470-477.
[21]LIANG X P,LIU Y,LI H Z,et al.Constitutive relationship for high temperature deformation of powder metallurgy Ti-47Al-2Cr-2Nb-0.2W alloy[J].Materials Design,2012,37:40-47.
[22]王耘涛,袁晓光,于宝义,等.过共晶Al-Si合金半固态触变成形本构方程[J].机械工程学报,2014,50(24):50-58.WANG Yuntao,YUAN Xiaoguang,YU Baoyi,et al.Semi-solid thixoforming constitutive equation of hypereutectic Al-Si alloy[J].Journal of Mechanical Engineering,2014,50(24):50-58.
[23]CHEN G,KE Z H,REN C Z,et al.Constitutive modeling for Ti-6Al-4V alloy machining based on the SHPB tests and simulation[J].Journal of Mechanical Engineering,2016,29(5):962-970.