对 Si CW/Al复合材料进行了热挤压 ,并用 SEM对拉伸断口进行了观察和分析。研究结果表明 ,热挤压能够明显地提高 Si CW/Al复合材料的塑性。热挤压导致复合材料塑性提高的原因是由于热挤压变形造成基体塑性的提高 ,以及晶须的折断和沿挤...对 Si CW/Al复合材料进行了热挤压 ,并用 SEM对拉伸断口进行了观察和分析。研究结果表明 ,热挤压能够明显地提高 Si CW/Al复合材料的塑性。热挤压导致复合材料塑性提高的原因是由于热挤压变形造成基体塑性的提高 ,以及晶须的折断和沿挤压方向定向排列的结果。展开更多
通过理论分析 ,证实了预变形调整 Al- Si Cw/Al复合材料热残余应力的可行性。采用压力铸造方法制造 Al- Si Cw/Al复合材料 ,试验研究了预变形对其残余应力及拉伸性能的影响。结果表明 ,Al- Si Cw/Al复合材料经预变形处理后残余应力明显...通过理论分析 ,证实了预变形调整 Al- Si Cw/Al复合材料热残余应力的可行性。采用压力铸造方法制造 Al- Si Cw/Al复合材料 ,试验研究了预变形对其残余应力及拉伸性能的影响。结果表明 ,Al- Si Cw/Al复合材料经预变形处理后残余应力明显降低 ,力学性能得到改善。展开更多
With a micro mechanical model, the feasibility of modification of thermal residual stress of the composites treated by tensile pre plastic deformation was analyzed. The relationship between pre plastic strain and vari...With a micro mechanical model, the feasibility of modification of thermal residual stress of the composites treated by tensile pre plastic deformation was analyzed. The relationship between pre plastic strain and variation of thermal residual stress was established. By using the method of tensile pre plastic deformation, the thermal residual stress in 20%SiC w/6061Al composites was modified. The results show that, with increasing tensile pre plastic strain, the tensile residual stress in the matrix was decreased to zero gradually, and then it was turned into compressive stress. By comparison, it was found that the changing tendency of the test results is similar to that of theoretical analysis. In addition, due to pre plastic deformation, the dislocation density in the matrix was increased, and the yield strength of the composites was improved. The increasing yield strength is mainly due to the decreasing tensile residual stress and the changing of distribution of dislocation in the matrix.展开更多
The application of compound parts of Al [AlBO] w/Al not only reduces the cost of the parts but also improves its properties. However, there is a large thermal residual stress between Al and [AlBO] w/Al, and it is harm...The application of compound parts of Al [AlBO] w/Al not only reduces the cost of the parts but also improves its properties. However, there is a large thermal residual stress between Al and [AlBO] w/Al, and it is harmful for practical application. From the theoretical analyses and experimental results, it was found that by the compressive pre plastic deformation perpendicular to the interface between Al and [AlBO] w/Al, the interlayer residual stress of compound parts can be reduced, while the mechanical properties of compound parts can be improved. [展开更多
The combustion behavior of Ti-Al-Mo-Zr-Sn-W alloy(TC25G)was studied in a high-temperature and high-speed air flow environment using the laser ignition method combined with ultra-high temperature infrared thermometer,s...The combustion behavior of Ti-Al-Mo-Zr-Sn-W alloy(TC25G)was studied in a high-temperature and high-speed air flow environment using the laser ignition method combined with ultra-high temperature infrared thermometer,scanning electron microscope,X-ray diffractometer,and transmission electron microscope.The burn-resistant performance of TC25G and TC11 alloys was compared.Meanwhile,the microstructural characteristics,crystal structure,and formation mechanism of the combustion products of TC25G alloy were analyzed in detail.The results show that the high-temperature and high-speed air flow promotes combustion within the air flow temperature range of 200–400℃and the air flow velocity range of 0–100 m/s.The combustion path advances along the direction of the air flow.The combustion of TC25G alloy mainly relies on the diffusion of the oxygen and the expansion of the combustion area caused by the movement of the melt.Based on the microstructure and composition of combustion product,it can be divided into the combustion zone,the melting zone,and the heat affected zone.During combustion,the formation of microstructures is closely correlated with the behavior of alloying elements and their selective combination with O.The major oxidation products of Ti are TiO and TiO_(2).The oxides formed by Mo and W hinder the movement of the melt during the combustion.Al and Zr tend to undergo internal oxidation.Al_(2)O_(3)precipitates on the surface of ZrO_(2),forming a protective oxide layer that inhibits the inward diffusion of O.Moreover,the element enrichment at the interface between the melting zone and the heat affected zone increases the melting point on the solid side,hindering the migration of the solid-liquid interface.展开更多
The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstru...The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstructure and interfacial strength of Sn−2Al/W90 interface were investigated.The ultrasound improved the wettability of Sn−2Al filler metal on W90 surface.As the ultrasonic power increased and ultrasonic time increased,the size of Al phase in seam decreased.The maximum value of Sn−2Al/W90 interfacial strength reached 30.1 MPa.Based on the acoustic pressure simulation and bubble dynamics,the intensity of cavitation effect was proportional to ultrasonic power.The generated high temperature and high pressure by cavitation effect reached 83799.6 K and 1.26×10^(14) Pa,respectively.展开更多
文摘With a micro mechanical model, the feasibility of modification of thermal residual stress of the composites treated by tensile pre plastic deformation was analyzed. The relationship between pre plastic strain and variation of thermal residual stress was established. By using the method of tensile pre plastic deformation, the thermal residual stress in 20%SiC w/6061Al composites was modified. The results show that, with increasing tensile pre plastic strain, the tensile residual stress in the matrix was decreased to zero gradually, and then it was turned into compressive stress. By comparison, it was found that the changing tendency of the test results is similar to that of theoretical analysis. In addition, due to pre plastic deformation, the dislocation density in the matrix was increased, and the yield strength of the composites was improved. The increasing yield strength is mainly due to the decreasing tensile residual stress and the changing of distribution of dislocation in the matrix.
文摘The application of compound parts of Al [AlBO] w/Al not only reduces the cost of the parts but also improves its properties. However, there is a large thermal residual stress between Al and [AlBO] w/Al, and it is harmful for practical application. From the theoretical analyses and experimental results, it was found that by the compressive pre plastic deformation perpendicular to the interface between Al and [AlBO] w/Al, the interlayer residual stress of compound parts can be reduced, while the mechanical properties of compound parts can be improved. [
基金China“Ye Qisun”Science Foundation Project of National Natural Science Foundation(U2141222)Innovation Fund(8F231527Z)。
文摘The combustion behavior of Ti-Al-Mo-Zr-Sn-W alloy(TC25G)was studied in a high-temperature and high-speed air flow environment using the laser ignition method combined with ultra-high temperature infrared thermometer,scanning electron microscope,X-ray diffractometer,and transmission electron microscope.The burn-resistant performance of TC25G and TC11 alloys was compared.Meanwhile,the microstructural characteristics,crystal structure,and formation mechanism of the combustion products of TC25G alloy were analyzed in detail.The results show that the high-temperature and high-speed air flow promotes combustion within the air flow temperature range of 200–400℃and the air flow velocity range of 0–100 m/s.The combustion path advances along the direction of the air flow.The combustion of TC25G alloy mainly relies on the diffusion of the oxygen and the expansion of the combustion area caused by the movement of the melt.Based on the microstructure and composition of combustion product,it can be divided into the combustion zone,the melting zone,and the heat affected zone.During combustion,the formation of microstructures is closely correlated with the behavior of alloying elements and their selective combination with O.The major oxidation products of Ti are TiO and TiO_(2).The oxides formed by Mo and W hinder the movement of the melt during the combustion.Al and Zr tend to undergo internal oxidation.Al_(2)O_(3)precipitates on the surface of ZrO_(2),forming a protective oxide layer that inhibits the inward diffusion of O.Moreover,the element enrichment at the interface between the melting zone and the heat affected zone increases the melting point on the solid side,hindering the migration of the solid-liquid interface.
基金supported by the National Natural Science Foundation of China(Nos.52105330,52175307)the Natural Science Foundation of Shandong Province,China(No.ZR2023JQ021)。
文摘The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstructure and interfacial strength of Sn−2Al/W90 interface were investigated.The ultrasound improved the wettability of Sn−2Al filler metal on W90 surface.As the ultrasonic power increased and ultrasonic time increased,the size of Al phase in seam decreased.The maximum value of Sn−2Al/W90 interfacial strength reached 30.1 MPa.Based on the acoustic pressure simulation and bubble dynamics,the intensity of cavitation effect was proportional to ultrasonic power.The generated high temperature and high pressure by cavitation effect reached 83799.6 K and 1.26×10^(14) Pa,respectively.
