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含钪Al-Cu-Li-Zr合金的热处理 总被引:1,自引:0,他引:1
通过显微组织观察和室温拉伸实验,研究了固溶处理制度和时效前预变形对含Sc的Al-Cu-Li-Zr合金力学性能与显微组织的影响。结果表明:适当提高固溶温度或延长固溶时间可以促进合金中过剩相的溶解,提高合金的强度和塑性;时效前适量的预变形促进T1相的大量弥散、细小析出,显著提高合金强度。过大的预变形量使T1相变得粗大且分布不均匀,合金强度降低。合金适宜的固溶制度为530℃,保温60min,适宜的预变形量为3.5%。 相似文献
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Trace amounts of La were utilized to improve the melting behaviors, microstructures, tensile properties and microhardness of Sn-3.0Ag-0.5Cu lead-free solder alloy. La has little effect on the melting behavior of Sn-3.0Ag-0.5Cu alloy according to the differential thermal analysis (DTA) tests. The X-ray diffraction (XRD) patterns show that β-Sn, Ag3Sn and Cu6Sn5 coexist in the as-cast solder alloys and LaSn3 phases emerge when adding 0.4% La. The microstructures modified by La are more uniform and much finer than that of baseline alloy, and the coarse LaSn3 particles with complex dendrites are observed by optical microscopy (OM) and scanning electron microscopy (SEM) when the addition of La is up to 0.4%. The composition of the LaSn3 phases is identified by energy-dispersive spectroscopy (EDS). There are considerable improvements in mechanical properties with 0.05% and 0.1% addition, but degenerations by adding 0.4%La. The Vickers microhardness of β-Sn and eutectic area are both enhanced with the addition of La and the microhardness of LaSn3 is much larger than those of β-Sn and eutectic area. 相似文献
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The mechanical properties and stress corrosion cracking (SCC) resistance of an Al-Zn-Cu-Mg-Sc-Zr alloy under different aging
conditions were investigated. The dependence of microstructure and mechanical properties on aging parameters was evaluated
by tensile test, hardness test and conductivity measurement. The results show that for the alloys with retrogression and re-aging
treatment (RRA), the conductivity increases with the retrogression time and temperature, while the tensile strength decreases.
The transmission electron microscopy (TEM) results show that the precipitates η(MgZn2) at grain boundary aggregate apparently with retrogression time and the precipitates inside the matrix exhibit the similar
distribution to T6 temper, which comprises fine GP zones, large η′(MgZn2) and η(MgZn2) phases. According to the mechanical properties and microstructure observations, the optimal RRA regime is recommended to
be 120 °C, 24 h + 180 °C, 30 min + 120 °C, 24 h. The strength level of the alloy after the optimum RRA treatment is similar
to that in T6 condition and the SCC resistance is improved obviously in contrast to T6 condition. 相似文献
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The flow stress behavior of Al-3.5Cu-1.5Li-0.25(Sc+Zr) alloy during hot compression deformation was studied by isothermal compression test using Gleeble-1500 thermal-mechanical simulator. Compression tests were preformed in the temperature range of 653-773 K and in the strain rate range of 0.001-10 s^-1 up to a true plastic strain of 0.7. The results indicate that the flow stress of the alloy increases with increasing strain rate at a given temperature,and decreases with increasing temperature at a given imposed strain rate. The relationship between the flow stress and the strain rate and the temperature was derived by analyzing the experimental data. The flow stress is in a hyperbolic sine relationship with the strain rate,and in an Arrhenius relationship with the temperature,which imply that the process of plastic deformation at an elevated temperature for this material is thermally activated. The flow stress of the alloy during the elevated temperature deformation can be represented by a Zener-Hollomon parameter with the inclusion of the Arrhenius term. The values of n,α and A in the analytical expressions of flow stress σ are fitted to be 5.62,0.019 MPa^-1 and 1.51×10^16 s^-1,respectively. The hot deformation activation energy is 240.85 kJ/mol. 相似文献
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研究了一种含Sc的Al-Cu-Li-Zr合金在不同时效状态下的晶间腐蚀和剥落腐蚀行为.结果表明:不同时效温度下峰时效态合金的晶间腐蚀和剥落腐蚀倾向随着时效温度的升高而增加;在160℃下时效,合金的晶间腐蚀和剥落腐蚀倾向随着时效时间的延长而增加.含Sc的Al-Cu-Li-Zr合金在EXCO溶液中进行的极化曲线测试结果也表现出相同的腐蚀趋势.微观组织观察分析表明,T1(Al2CuLi)相和无沉淀析出带(PFZ)是引起合金腐蚀敏感性增加的主要因素. 相似文献
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采用热模拟实验对含Sc超高强Al-Zn-Cu-Mg-Zr合金在应变速率为0.001~10s-1、变形温度为380~470℃的条件下进行了热压缩实验.研究了实验合金的流变应力行为和微观组织演变.结果表明:流变应力随变形温度升高而下降;随应变速率增加峰值应力也相应增加.随变形温度升高和应变速率降低,合金动态再结晶的程度加深,亚晶尺寸变大.含Sc超高强Al-Zn-Cu-Mg-Zr合金,形成了Al3Sc弥散相,该相可强烈抑制再结晶.合金主要软化机制为动态回复伴随动态再结晶. 相似文献
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通过晶间腐蚀、剥落腐蚀和极化曲线试验,结合扫描电镜和透射电镜等分析手段,研究了含钪Al-Cu-Li-Zr合金在不同时效状态下的晶间腐蚀和剥落腐蚀行为.结果表明,合金在自然时效状态下具有较好的抗晶间腐蚀和剥落腐蚀能力,但随着时效时间的延长,其晶间腐蚀与剥落腐蚀倾向逐渐增加;在4.0 mol/L NaCl 0.1 mol/L HNO3 0.4 mol/L KNO3(EXCO)溶液中进行的极化曲线测试也表现出相同的趋势.透射电镜观察表明,自然时效态合金未析出Г1相,欠时效态合金中有少量细小短棒状Г1相析出,随着时效时间的延长,Г1相逐渐粗化,过时效时合金中出现较宽的无沉淀带(PFZ).由于合金中Г1相和PFZ的开路电位都比铝基体低,在腐蚀过程中作为阳极相优先溶解,从而引起合金晶间腐蚀和剥落腐蚀. 相似文献