制备了含稀土La的6063铝合金,并研究了La含量对铝合金的显微组织及时效后硬度、抗拉强度和伸长率的影响。研究表明,稀土La对6063合金晶粒有良好的细化作用,在添加La的铝合金组织中,一部分较大的析出相是Al Si Mg Fe化合物,且铁含量较高...制备了含稀土La的6063铝合金,并研究了La含量对铝合金的显微组织及时效后硬度、抗拉强度和伸长率的影响。研究表明,稀土La对6063合金晶粒有良好的细化作用,在添加La的铝合金组织中,一部分较大的析出相是Al Si Mg Fe化合物,且铁含量较高;另一部分析出相是Al Si Mg Fe La的复杂化合物,其形状多呈较小的粒状。200℃等温时效时,随着时效时间的延长,铝合金硬度迅速升高,在120 min左右达到最大。同时,随着La含量的增加,合金的硬化峰值上升,当La含量为0.2 wt%左右时,时效硬化峰值达到最高。另外,加入适量La可增加合金的抗拉强度和伸长率。未添加La的铝合金其断口组织分布着较大的不规则韧窝,而添加少量La的铝合金其断口上细小的韧窝增多。展开更多
A new type of hybrid SiC foam-SiC particles-Al composites used as an electronic packaging substrate material were fabricated by squeeze casting technique. The mechanical properties and the fracture mechanism of the hy...A new type of hybrid SiC foam-SiC particles-Al composites used as an electronic packaging substrate material were fabricated by squeeze casting technique. The mechanical properties and the fracture mechanism of the hybrid composites were investigated. The influence of SiC particles and foam hybrid reinforcement on the behavior of the composites was studied. The results show that the interface bonding in the hybrid composites is good for the composites with the unique double interpenetrating structure. The compressive strength of the hybrid composite reinforced by the SiC with the volume fraction of 59.9% is 680 MPa,which is higher than that of any other composites with the same volume fraction of SiC particles reinforcement.展开更多
Dissimilar joints(DSJs)of ferrous and non-ferrous metals have huge technological importance in the frontiers of newdesigns in new machineries and improved design of conventional systems.This investigation was undertak...Dissimilar joints(DSJs)of ferrous and non-ferrous metals have huge technological importance in the frontiers of newdesigns in new machineries and improved design of conventional systems.This investigation was undertaken to improve mechanicalproperties of joints of two dissimilar metals:one is Ti-based and the other is Fe-based.DSJs were processed using bonding pressurefrom1to9MPa in step of2MPa at750°C for60min.Properties of the DSJs of these two metals using different mechanisms andmethods were compared with the present research for verification.Experimental results from the diffusion bonding mechanism forjoining the dissimilar metals validated the improvement in properties.Superior mechanical properties of dissimilar-metals joints wereachieved mainly due to the third non-ferrous metallic foil,Ni of^200-?m thickness,which avoided the formation of brittleFe-Ti-based intermetallics in the diffusion zone.DSJs processed are able to achieve maximum strength of^560MPa along withsubstantial ductility of^11.9%,which is the best ever reported in the literatures so far.Work hardening effect was detected in theDSJs when the bonding was processed at5MPa and above.Bulging ratio of the non-ferrous metal(Ti-based)was much higher thanthat of the ferrous metal(SS)of the DSJs processed.SEM analysis was carried out to know the details of reaction zone,while XRDwas carried out to support the SEM results.Reasons for change in mechanical,physical,and fracture properties of the DSJs with theprocess parameter variations were clarified.展开更多
文摘制备了含稀土La的6063铝合金,并研究了La含量对铝合金的显微组织及时效后硬度、抗拉强度和伸长率的影响。研究表明,稀土La对6063合金晶粒有良好的细化作用,在添加La的铝合金组织中,一部分较大的析出相是Al Si Mg Fe化合物,且铁含量较高;另一部分析出相是Al Si Mg Fe La的复杂化合物,其形状多呈较小的粒状。200℃等温时效时,随着时效时间的延长,铝合金硬度迅速升高,在120 min左右达到最大。同时,随着La含量的增加,合金的硬化峰值上升,当La含量为0.2 wt%左右时,时效硬化峰值达到最高。另外,加入适量La可增加合金的抗拉强度和伸长率。未添加La的铝合金其断口组织分布着较大的不规则韧窝,而添加少量La的铝合金其断口上细小的韧窝增多。
基金Project(50765005) supported by the National Natural Science Foundation of ChinaProject(01306016) supported by the Science Research Foundation of East China Jiaotong University, China
文摘A new type of hybrid SiC foam-SiC particles-Al composites used as an electronic packaging substrate material were fabricated by squeeze casting technique. The mechanical properties and the fracture mechanism of the hybrid composites were investigated. The influence of SiC particles and foam hybrid reinforcement on the behavior of the composites was studied. The results show that the interface bonding in the hybrid composites is good for the composites with the unique double interpenetrating structure. The compressive strength of the hybrid composite reinforced by the SiC with the volume fraction of 59.9% is 680 MPa,which is higher than that of any other composites with the same volume fraction of SiC particles reinforcement.
文摘Dissimilar joints(DSJs)of ferrous and non-ferrous metals have huge technological importance in the frontiers of newdesigns in new machineries and improved design of conventional systems.This investigation was undertaken to improve mechanicalproperties of joints of two dissimilar metals:one is Ti-based and the other is Fe-based.DSJs were processed using bonding pressurefrom1to9MPa in step of2MPa at750°C for60min.Properties of the DSJs of these two metals using different mechanisms andmethods were compared with the present research for verification.Experimental results from the diffusion bonding mechanism forjoining the dissimilar metals validated the improvement in properties.Superior mechanical properties of dissimilar-metals joints wereachieved mainly due to the third non-ferrous metallic foil,Ni of^200-?m thickness,which avoided the formation of brittleFe-Ti-based intermetallics in the diffusion zone.DSJs processed are able to achieve maximum strength of^560MPa along withsubstantial ductility of^11.9%,which is the best ever reported in the literatures so far.Work hardening effect was detected in theDSJs when the bonding was processed at5MPa and above.Bulging ratio of the non-ferrous metal(Ti-based)was much higher thanthat of the ferrous metal(SS)of the DSJs processed.SEM analysis was carried out to know the details of reaction zone,while XRDwas carried out to support the SEM results.Reasons for change in mechanical,physical,and fracture properties of the DSJs with theprocess parameter variations were clarified.
