The influence of Mo and ZrO_(2)nanoparticles addition on the interfacial properties and shear strength of Sn58Bi solder joint was investigated.The interfacial microstructures of Sn58Bi/Cu,Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(...The influence of Mo and ZrO_(2)nanoparticles addition on the interfacial properties and shear strength of Sn58Bi solder joint was investigated.The interfacial microstructures of Sn58Bi/Cu,Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints were analysed using a scanning electron microscope(SEM)coupled with energy dispersive X-ray(EDX)and the X-ray diffraction(XRD).Intermetallic compounds(IMCs)of MoSn_(2)are detected in the Sn58Bi+Mo/Cu solder joint,while SnZr,Zr_(5)Sn_(3),ZrCu and ZrSn_(2)are detected in Sn58Bi+ZrO_(2)/Cu solder joint.IMC layers for both composite solders comprise of Cu_(6)Sn_(5) and Cu_(3)Sn.The SEM images of these layers were used to measure the IMC layer’s thickness.The average IMC layer’s thickness is 1.4431μm for Sn58Bi+Mo/Cu and 0.9112μm for Sn58Bi+ZrO_(2)/Cu solder joints.Shear strength of the solder joints was investigated via the single shear lap test method.The average maximum load and shear stress of the Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints are increased by 33%and 69%,respectively,as compared to those of the Sn58Bi/Cu solder joint.By comparing both composite solder joints,the latter prevails better as adding smaller sized ZrO_(2)nanoparticles improves the interfacial properties granting a stronger solder joint.展开更多
Significant progress has been made in recent years in understanding and modelling the rheology of semi-solid metals.These models show the effects of the microstructure in terms of size and morphology of globules on th...Significant progress has been made in recent years in understanding and modelling the rheology of semi-solid metals.These models show the effects of the microstructure in terms of size and morphology of globules on the material response.More recently it has been shown that semi-solid metals can behave as compacted granular materials such as sand.A particular signature of such deformation is that the deformation becomes concentrated into shear bands which are 10-20 grains wide.Such bands have also been observed in a range of cast products.Recently, it has been clearly shown that shear bands in high pressure die cast (HPDC) products are also the results of Reynolds dilatancy.Shear bands are also known to be a common feature in semi-solid metal products.The segregation banding in semi-solid metal (SSM) material and its dependence of plunger velocity were investigated.Shaped castings were made with the RHEOMETALTM process with a range of different plunger velocities.The microstructural characteristics were investigated, with a particular emphasis on shear bands.It is shown that ingate velocities influence the location and characteristics of the shear bands.展开更多
Mechanical properties of （Cu50Zr43Al7）100 Nbx （x=0,1,3,6,9） bulk metallic glasses rods with a diameter of 2.5 mm prepared by suction casting method were studied. The results of uniaxial compression tests at room t...Mechanical properties of （Cu50Zr43Al7）100 Nbx （x=0,1,3,6,9） bulk metallic glasses rods with a diameter of 2.5 mm prepared by suction casting method were studied. The results of uniaxial compression tests at room temperture show that the best mechanical properties of 2.8% and 1.98 GPa for plastic strain and fracture strength, respectively, in the sample with x=3. Microstructure, fracture surface and shear bands of the samples were observed by SEM and XRD methods.展开更多
Dual equal channel lateral extrusion(DECLE)process with various passes followed by sheet extrusion process was performed to produce fine-grained ZK60 alloy sheets.The coarse grain structure of the annealed sample afte...Dual equal channel lateral extrusion(DECLE)process with various passes followed by sheet extrusion process was performed to produce fine-grained ZK60 alloy sheets.The coarse grain structure of the annealed sample after applying sheet extrusion(size:68μm)changed to fine grains of 6.0 and 5.2μm after 3 and 5 passes of DECLE and following extrusion.The hot shear deformation behavior of samples was studied by developing constitutive equations based on shear punch test(SPT)results.SPT was carried out in the temperature range of 200−300℃ and strain rate range of 0.003−0.33 s^(–1).The activation energy of 125−139 kJ/mol and the stress exponent of 3.5−4.2 were calculated for all conditions,which indicated that dislocation creep,controlled by dislocation climb and solute drag mechanism,acted as the main hot deformation mechanism.It was concluded that material constants of n and Q are dependent on the microstructural factors such as grain size and second phase particle fraction,and the relationship of which was anticipated using a 3D surface curve.Moreover,the similar strong basal texture of extruded sheets gave rise to the same deformation mechanisms during SPT and similar n and Q values for ZK60 alloy.展开更多
文摘The influence of Mo and ZrO_(2)nanoparticles addition on the interfacial properties and shear strength of Sn58Bi solder joint was investigated.The interfacial microstructures of Sn58Bi/Cu,Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints were analysed using a scanning electron microscope(SEM)coupled with energy dispersive X-ray(EDX)and the X-ray diffraction(XRD).Intermetallic compounds(IMCs)of MoSn_(2)are detected in the Sn58Bi+Mo/Cu solder joint,while SnZr,Zr_(5)Sn_(3),ZrCu and ZrSn_(2)are detected in Sn58Bi+ZrO_(2)/Cu solder joint.IMC layers for both composite solders comprise of Cu_(6)Sn_(5) and Cu_(3)Sn.The SEM images of these layers were used to measure the IMC layer’s thickness.The average IMC layer’s thickness is 1.4431μm for Sn58Bi+Mo/Cu and 0.9112μm for Sn58Bi+ZrO_(2)/Cu solder joints.Shear strength of the solder joints was investigated via the single shear lap test method.The average maximum load and shear stress of the Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints are increased by 33%and 69%,respectively,as compared to those of the Sn58Bi/Cu solder joint.By comparing both composite solder joints,the latter prevails better as adding smaller sized ZrO_(2)nanoparticles improves the interfacial properties granting a stronger solder joint.
文摘Significant progress has been made in recent years in understanding and modelling the rheology of semi-solid metals.These models show the effects of the microstructure in terms of size and morphology of globules on the material response.More recently it has been shown that semi-solid metals can behave as compacted granular materials such as sand.A particular signature of such deformation is that the deformation becomes concentrated into shear bands which are 10-20 grains wide.Such bands have also been observed in a range of cast products.Recently, it has been clearly shown that shear bands in high pressure die cast (HPDC) products are also the results of Reynolds dilatancy.Shear bands are also known to be a common feature in semi-solid metal products.The segregation banding in semi-solid metal (SSM) material and its dependence of plunger velocity were investigated.Shaped castings were made with the RHEOMETALTM process with a range of different plunger velocities.The microstructural characteristics were investigated, with a particular emphasis on shear bands.It is shown that ingate velocities influence the location and characteristics of the shear bands.
文摘Mechanical properties of （Cu50Zr43Al7）100 Nbx （x=0,1,3,6,9） bulk metallic glasses rods with a diameter of 2.5 mm prepared by suction casting method were studied. The results of uniaxial compression tests at room temperture show that the best mechanical properties of 2.8% and 1.98 GPa for plastic strain and fracture strength, respectively, in the sample with x=3. Microstructure, fracture surface and shear bands of the samples were observed by SEM and XRD methods.
文摘Dual equal channel lateral extrusion(DECLE)process with various passes followed by sheet extrusion process was performed to produce fine-grained ZK60 alloy sheets.The coarse grain structure of the annealed sample after applying sheet extrusion(size:68μm)changed to fine grains of 6.0 and 5.2μm after 3 and 5 passes of DECLE and following extrusion.The hot shear deformation behavior of samples was studied by developing constitutive equations based on shear punch test(SPT)results.SPT was carried out in the temperature range of 200−300℃ and strain rate range of 0.003−0.33 s^(–1).The activation energy of 125−139 kJ/mol and the stress exponent of 3.5−4.2 were calculated for all conditions,which indicated that dislocation creep,controlled by dislocation climb and solute drag mechanism,acted as the main hot deformation mechanism.It was concluded that material constants of n and Q are dependent on the microstructural factors such as grain size and second phase particle fraction,and the relationship of which was anticipated using a 3D surface curve.Moreover,the similar strong basal texture of extruded sheets gave rise to the same deformation mechanisms during SPT and similar n and Q values for ZK60 alloy.
