汽车用Al-7Si-0.5V-0.3In铸造铝合金的性能研究

采用不同的浇注温度对汽车用Al-7Si-0.5V-0.3In铝合金进行了铸造试验,并进行了强度和耐磨损性能的测试、比较与分析。结果表明:随浇注温度的升高,试样的抗拉强度先增大后减小,磨损体积先减小后增大。与710℃浇注温度相比,760℃浇注温度下试样的抗拉强度增大了12.81%,磨损体积减小了25.46%。Al-7Si-0.5V-0.3In铝合金铸造试样的浇注温度优选为760℃。     

机械紧固件用新型钛合金的锻造温度优化

采用不同的锻造温度对机械紧固件用新型钛合金进行了锻造试验,并进行了耐磨损性能和高温抗氧化性能的测试与分析。结果表明:随始锻温度从1020℃升高至1100℃,试样的磨损体积和单位面积质量增重先减小后增大,与1020℃始锻时相比,始锻温度为1080℃时试样的磨损体积减小了35. 48%,单位面积质量增重减小了36. 36%。随终锻温度从800℃升高至880℃,试样的磨损体积和单位面积质量增重先减小后增大,与800℃终锻时相比,终锻温度为860℃时试样的磨损体积减小了42. 86%,单位面积质量增重减小39. 13%。机械紧固件用新型钛合金Ti-3Al-5Mo-4. 5V-1Sr-0. 5Ce的始锻温度优选为1080℃、终锻温度不低于860℃。     

液态模锻AZ31镁合金汽车轮毂的性能分析

采用不同的浇注温度和比压对AZ31镁合金汽车轮毂进行了液态模锻成形,并进行了显微组织、耐磨损性能和耐腐蚀性能的测试与分析。结果表明:随比压和浇注温度的增加,轮毂试样的平均晶粒尺寸和磨损体积均先减小后增大,腐蚀电位先正移后负移,耐磨损性能和耐腐蚀性能先提升后下降。与30 MPa比压相比较,50 MPa比压时试样的平均晶粒尺寸和磨损体积分别减小了27.39%、41.67%,腐蚀电位正移了36 m V。与680℃浇注温度相比,700℃浇注时试样的平均晶粒尺寸和磨损体积分别减小了33.33%、47.5%,腐蚀电位正移了47 m V。AZ31镁合金汽车轮毂的液态模锻工艺参数优选为:50 MPa比压、700℃浇注温度。     

液态模锻工艺对机械活塞低温性能的影响

采用不同的压力和浇注温度进行了Al-12Si-1Cu-1Mg-0.5Ce新型铝合金机械活塞的液态模锻成形,并进行了试样的冲击性能和耐磨损性能的测试与分析。结果表明:随浇注温度从650℃提高至800℃、压力从10 MPa增加至50 MPa,活塞的冲击性能和耐磨损性能均先提高后下降。优化的浇注温度和压力分别为725℃、30 MPa。     

新型铝合金机械涡旋盘的挤压铸造工艺及性能研究

对ZL111+0.5V新型铝合金涡旋盘进行了挤压铸造成型,并进行了磨损性能和表面硬度的测试与分析。结果表明:随浇注温度和挤压铸造压力的提升,试样的磨损性能先提高后下降。710℃浇注温度下试样的磨损体积较680℃浇注时减小了44.9%,表面硬度提高了34.7%;24 MPa挤压铸造压力下试样的磨损体积较18 MPa时减小了34.1%,表面硬度提高了26.7%。ZL111+0.5V铝合金涡旋盘的挤压铸造工艺参数优选为:浇注温度710℃、挤压铸造压力24 MPa。     

压力铸造Al-10Si-3Cu-0.5V-0.2Ti铝合金机械外壳的性能研究

采用不同的浇注温度和保压比压对Al-10Si-3Cu-0.5V-0.2Ti铝合金机械外壳试样进行了压力铸造试验,并进行了耐磨损性能和耐腐蚀性能的测试与分析。结果表明:随浇注温度和保压比压的升高,试样的磨损体积先减小再增大,腐蚀电位先正移后负移,耐磨、耐腐蚀性能均表现为先提升再下降。在720℃浇注温度和60MPa保压比压下,试样的磨损体积最小,腐蚀电位最正。在这个条件下磨损体积为22×10~(-3)mm~3,腐蚀电位为0.846V。     

挤压温度对新型镁合金机械外壳件性能的影响

采用不同的挤压温度对Mg-8Al-0.6Zn-0.5Ti-0.3V新型镁合金机械外壳件进行挤压成形试验,并取样进行冲击性能和耐腐蚀性能测试。结果表明:随挤压温度升高,挤压件试样冲击吸收功先增大再减小,腐蚀电位先正移后逐渐负移,单位面积腐蚀失重先减小后增大,冲击性能和耐腐蚀性能先提升后下降。与300℃挤压温度相比,380℃挤压温度试样的冲击吸收功增大了58.97%,腐蚀电位正移了34 mV,单位面积的腐蚀失重减小了37.8%。Mg-8Al-0.6Zn-0.5Ti-0.3V新型镁合金机械外壳件的挤压温度优选为380℃。     

挤压工艺参数对铝合金汽车方管性能的影响

进行了Al-0.7Mg-0.4Si-0.3V-0.3In铝合金汽车方管试样的挤压成形,并进行了不同挤压温度和挤压比下的力学性能和耐磨损性能的测试、对比及分析。结果表明:随挤压温度从380℃增至460℃、挤压比从15增至35,试样强度先提高后下降,磨损体积先减小后增大。在挤压温度440℃和挤压比15时挤压的试样抗拉强度和屈服强度最大,断后伸长率最小,磨损体积最小。铝合金汽车方管的挤压工艺参数优选为挤压温度440℃和挤压比25。     

挤压温度对建筑装饰用新型铝合金性能的影响

为了研究挤压温度对建筑装饰用新型铝合金6061-InTi性能的影响,采用不同的挤压温度对合金试样进行了挤压成形,并进行了试样在室温条件下的夏比摆锤冲击和中性盐雾腐蚀试验,分析了挤压温度对合金试样冲击性能和耐腐蚀性能的影响规律。结果表明:随挤压温度的升高,试样的冲击吸收功先增大后缓慢减小,单位面积质量损失量先减小后缓慢增大,冲击性能和耐腐蚀性能均先提升后降低;在挤压速度3 m·min-1、模具预热温度280℃和挤压比25均不变的情况下,与400℃挤压温度相比,460℃挤压温度下的冲击吸收功增大了32. 65%,单位面积质量损失量减小了40. 58%。建筑装饰用新型铝合金6061-InTi试样的挤压温度优选为460℃。     

液态模锻工艺参数对汽车铝合金轮辋性能的影响

采用不同的液态模锻工艺参数对汽车铝轮辋进行了成形,并进行了磨损和腐蚀性能的测试与分析。结果表明:比压为120 MPa时,与660℃浇注相比,720℃浇注试样的磨损体积减小了32%,腐蚀电位正移了116 m V。浇注温度为720℃时,与100 MPa成形的试样相比,120 MPa成形时试样的磨损体积减小了21%,腐蚀电位正移了92 m V。随浇注温度从660℃升高至740℃、比压从100 MPa升高至130 MPa,汽车铝轮辋的耐磨损性能和耐腐蚀性能均先提高后下降。适宜的浇注温度和比压分别为720℃和120 MPa。     

锻造和热处理对Al-Si和Al-Pb轴承合金在油润滑条件下耐磨性的影响

研究了锻造态和热处理态不同成分铝基轴承合金在油润滑条件下的摩擦行为，以及材料的硬度、热处理制度和锻造对材料耐磨性的影响。所用材料是 Al-8.5Si-3.5Cu 和 Al-15Pb-3.7Cu-1.5Si-1.1Fe。在锻造过程中，应变范围为10%~20%。并对材料进行T6热处理。在销-盘式磨损试验机上对材料的摩擦性能进行测试。结果表明，锻造过程使材料的硬度得到增加；铸造应变在10%~20%的范围内对材料的摩擦磨损影响不明显。     

Brazing of 6061 aluminum alloy/Ti-6Al-4V using Al-Si-Cu-Ge filler metals

Al-8.4Si-20Cu-10Ge and mixed rare-earth elements (Re) containing Al-8.4Si-20Cu-10Ge-0.1Re filler metals were used for brazing of 6061 aluminum alloy/Ti-6Al-4V. The addition of 20 wt.% copper and 10 wt.% germanium into the Al-12Si filler metal lowered the solidus temperature from 586 °C to 489 °C and the liquidus temperature from 592 °C to 513 °C. The addition of 0.1 wt.% rare-earth elements into Al-8.4Si-20Cu-10Ge alloy caused remarkable Al-rich phase refinement and transformed the needle-like Al₂Cu intermetallic compounds into block-like shapes. Shear strengths of the 6061 aluminum alloy/Ti-6Al-4V joints with the two brazing filler metals, Al-8.4Si-20Cu-10Ge and Al-8.4Si-20Cu-10Ge-0.1Re, varied insignificantly with brazing periods of 10-60 min. The average shear strength of the 6061 aluminum alloy/Ti-6Al-4V joints brazed with Al-8.4Si-20Cu-10Ge at 530 °C was about 20 MPa. Rare-earth elements appeared to improve the reaction of the Al-8.4Si-20Cu-10Ge filler metal with Ti-6Al-4V. The joint shear strength of the 6061 aluminum alloy/Ti-6Al-4V with Al-8.4Si-20Cu-10Ge-0.1Re reached about 51 MPa.     

B对Al-13Si-0.3Mg合金流动性的影响

采用浇注螺旋型试样的方法测量了B对Al-13Si-0．3Mg合金流动性的作用；并通过温度校正的方法校正了浇注温度的误差对测量结果的影响。研究发现随B含量的增加，合金的流动性明显提高。采用对凝固中期的合金进行液淬的方法研究了该合金的凝固方式。根据合金凝固后的组织及合金凝固的方式分析了B影响Al-13Si-0．3Mg合金流动性的原因。     

热循环温度对Ti-6Al-4V合金组织和力学性能的影响

对上限温度为500、650、800℃高温短时热循环200次后的Ti-6Al-4V合金室温力学性能和组织进行了研究。结果表明:循环温度对合金强度影响较为明显,循环温度的升高使合金抗拉强度降低;分析认为:温度高于650℃,实验合金组织中β相逐渐分解碎化,β相含量减少和α晶粒逐渐长大是强度降低的主要原因。     

Degassing effect of ultrasonic vibration in molten melt and semi-solid slurry of Al-Si alloys

In the process of semi-solid slurry preparation with direct ultrasonic vibration (UV) by dipping the horn into the melt, one of the questions is whether the gas content in the melt would be increased or not by the cavitation effect of ultrasonic vibration. By application of quantitative gas content measurement technique, this paper investigated the effect of the ultrasonic vibration on the gas content of both the melt and the semi-solid slurry of Al-Si alloys, and the variations of the gas contents in two kinds of aluminum alloys, i.e., A356 alloy and Al-20Si-2Cu-1Ni-0.6RE alloy (Al-20Si for short). The results show that ultrasonic vibration has an obvious degassing effect on the molten melt, especially on the semi-solid slurry of Al-Si alloy which is below the liquidus temperature by less than 20 ℃. The ultrasonic degassing efficiency of the A356 alloy decreases with the reduction of the initial gas content in the melt, and it is nearly unchanged for the Al-20Si alloy. The gas content of both alloys decreases when the ultrasonic vibration time is increased. The best vibration time for Al-20Si alloy at the liquid temperature of 710 ℃ and semi-solid temperature of 680 ℃ is 60 s and 90 s, respectively; and the degassing efficiency is 48% and 35%, respectively. The mechanism of ultrasonic degassing effect is discussed.     

挤压铸造对Al-Cu合金显微组织及溶质分布的影响

研究了挤压铸造工艺条件下,工艺参数对Al-5Cu-0.4Mn合金显微组织及Cu元素分布的影响。结果表明,合金在25MPa压力下成形时,初生α-Al晶粒尺寸得到明显细化;浇注温度越高组织变得越粗大;升高模具预热温度,晶粒尺寸增大且分布不均匀。挤压铸造改变重力铸造条件下Cu的逆偏析现象,从铸件边缘往心部的Cu含量呈现增加的趋势,主要原因为晶间富铜液相在压力的强制补缩下,通过枝晶骨架通道被挤向铸件内侧。Cu在α-Al基体中的固溶度随着压力的增大而增加;沿径向远离铸件心部,α-Al晶内Cu含量逐渐增加。在挤压力为100MPa、浇注温度为680～730℃、模具温度为200℃的工艺条件下,可获得晶粒细小、组织致密、宏观偏析少的Al-5Cu-0.4Mn合金挤压铸件。     

Microstructure prediction of two-phase titanium alloy during hot forging using artificial neural networks and FE simulation

The microstructural evolution of titanium alloy under isothermal and non-isothermal hot forging conditions was predicted using artificial neural networks (ANN) and finite element (FE) simulation. In the present work, the change in phase volume fraction, grain size, and the volume fraction of dynamic globularization were modelled considering hot working conditions. Initially, an ANN model was developed for steady-state phase volume fraction. The input parameters were the alloy chemical composition (Al, V, Fe, O, and N) and the holding temperature, and the output parameter was the alpha/beta phase volume fraction at steady state. The non-steady state phase volume fraction under non-isothermal conditions was subsequently modelled on the basis of 4 input parameters such as initial specimen temperature, die (or environment) temperature, steady-state phase volume fraction at die (or environment) temperature, and elapsed time during forging. Resulting ANN models were coupled with the FE simulation (DEFORM-3D) in order to predict the variation of phase volume fraction during isothermal and non-isothermal forging. In addition, a grain size variation and a globularization model were developed for hot forging. To validate the predicted results from the models, Ti-6Al-4V alloy was hot-worked at various conditions and then the resulting microstructures were compared with simulated data. Comparisons between model predictions and experimental data indicated that the ANN model holds promise for microstructure evolution in two phase Ti-6Al-4V alloy.     

浇注温度和细化剂对半固态A356合金组织的影响

采用低温铸造和晶粒细化复合工艺制备A356合金半固态坯料,研究了浇注温度和细化剂(Al-5Ti-1B)添加量对半固态坯料组织的影响。结果表明,随着浇注温度从715℃降到635℃,α-Al晶粒形貌从树枝晶向蔷薇状形态再到等轴晶组织变化,浇注温度越低,晶粒越细小圆整。当浇注温度降到615℃时,晶粒开始出现粗化和不均匀。在相同温度下,随着晶粒细化剂添加量的增加,晶粒更加细小,但细化效果随着添加量的增加变得不明显。当浇注温度低于635℃时添加细化剂,晶粒尺寸和形貌无明显变化。低过热度浇注和晶粒细化复合工艺制备A356合金半固态坯料的最佳工艺条件是:浇注温度为635~655℃,细化剂添加量为0.1%~0.2%。