The microstructure,diffusional and mechanical bonding behavior and microhardness distribution of laminated composites fabricated by ECAP process were investigated.Al?Cu and Cu?Ni laminated composites were produced by ...The microstructure,diffusional and mechanical bonding behavior and microhardness distribution of laminated composites fabricated by ECAP process were investigated.Al?Cu and Cu?Ni laminated composites were produced by ECAP process up to4passes at room temperature and high temperature(300°C).The results of microstructure characterization by SEM and shear strength test revealed that the joints between the layers of4-pass ECAPed samples were considerably stronger than those of1-pass ECAPed samples due to tolerating higher values of plastic deformations during ECAP.Furthermore,shear strength data showed that increasing ECAP temperature caused a notable increase in shear strength of the specimens.The reason lies in the formation of diffusional joint between the interface of both Al/Cu and Cu/Ni layers at high temperature.The shear bonding strength of ECAPed Cu/Ni/Cu composite at high temperature was remarkably higher than that of ECAPed Cu/Al/Cu composite.展开更多
It is well known that the finer particle of cementing material has more pozzolanic reaction than the coarser. This paper investigates the shear properties of geocomposite soil with various particle sizes of bottom ash...It is well known that the finer particle of cementing material has more pozzolanic reaction than the coarser. This paper investigates the shear properties of geocomposite soil with various particle sizes of bottom ash. The geocomposite soil （GCS） in this study consists of dredged soil, bottom ash and cement for recycling dredged soil and bottom ash. Three different particle sizes of bottom ash passing No. 4 sieve, No. 40 sieve, and No. 140 sieve were added into soil mixtures, namely as GCS 4, GCS 40, and GCS 140, respectively. These bottom ashes have the same chemical component except for different particle sizes. Several mixtures were prepared with various contents of bottom ash ranging from 0 to 100% at 50% intervals by the weight of dry dredged soil. In this study, several series of unconfined compression test were carried out on the mixtures with various curing times. It is found that the unconfined compressive strength is a function of curing time and bottom ash content. For the curing time less than 28 days, the GCS 4 has higher unconfined compressive strength than the GCS 40 and GCS 140 due to the interlocking effect and friction between the particles with angular shape of coarse bottom ash. For the curing time larger than 28 days, the GCS 140 has higher strength due to the pozzolanic reaction. However, the ratios of secant modulus to unconfined compressive strength of three mixtures are almost the same, and in range of （46-100）, regardless of mixing condition and curing time.展开更多
文摘The microstructure,diffusional and mechanical bonding behavior and microhardness distribution of laminated composites fabricated by ECAP process were investigated.Al?Cu and Cu?Ni laminated composites were produced by ECAP process up to4passes at room temperature and high temperature(300°C).The results of microstructure characterization by SEM and shear strength test revealed that the joints between the layers of4-pass ECAPed samples were considerably stronger than those of1-pass ECAPed samples due to tolerating higher values of plastic deformations during ECAP.Furthermore,shear strength data showed that increasing ECAP temperature caused a notable increase in shear strength of the specimens.The reason lies in the formation of diffusional joint between the interface of both Al/Cu and Cu/Ni layers at high temperature.The shear bonding strength of ECAPed Cu/Ni/Cu composite at high temperature was remarkably higher than that of ECAPed Cu/Al/Cu composite.
文摘It is well known that the finer particle of cementing material has more pozzolanic reaction than the coarser. This paper investigates the shear properties of geocomposite soil with various particle sizes of bottom ash. The geocomposite soil （GCS） in this study consists of dredged soil, bottom ash and cement for recycling dredged soil and bottom ash. Three different particle sizes of bottom ash passing No. 4 sieve, No. 40 sieve, and No. 140 sieve were added into soil mixtures, namely as GCS 4, GCS 40, and GCS 140, respectively. These bottom ashes have the same chemical component except for different particle sizes. Several mixtures were prepared with various contents of bottom ash ranging from 0 to 100% at 50% intervals by the weight of dry dredged soil. In this study, several series of unconfined compression test were carried out on the mixtures with various curing times. It is found that the unconfined compressive strength is a function of curing time and bottom ash content. For the curing time less than 28 days, the GCS 4 has higher unconfined compressive strength than the GCS 40 and GCS 140 due to the interlocking effect and friction between the particles with angular shape of coarse bottom ash. For the curing time larger than 28 days, the GCS 140 has higher strength due to the pozzolanic reaction. However, the ratios of secant modulus to unconfined compressive strength of three mixtures are almost the same, and in range of （46-100）, regardless of mixing condition and curing time.
