研究了 Si CW/L D2复合材料管材的热挤压成形工艺。研究结果表明 ,采用传统的热挤压方法得到的 Si CW/L D2复合材料管材外表面具有严重的表面缺陷 ;采用包覆挤压方法 ,可使 Si CW/L D2复合材料管材外表面覆盖一层均匀的铝包覆层 ,消除...研究了 Si CW/L D2复合材料管材的热挤压成形工艺。研究结果表明 ,采用传统的热挤压方法得到的 Si CW/L D2复合材料管材外表面具有严重的表面缺陷 ;采用包覆挤压方法 ,可使 Si CW/L D2复合材料管材外表面覆盖一层均匀的铝包覆层 ,消除了表面缺陷 ,证明包覆挤压方法是一种有效的 Si展开更多
The 2 mm-thick SiCp/LD2 composite plates were electron beam welded at different heat inputs. The microstructures of welds were investigated by OM, TEM, SEM, and XRD, and the properties of welds were measured with MTS-...The 2 mm-thick SiCp/LD2 composite plates were electron beam welded at different heat inputs. The microstructures of welds were investigated by OM, TEM, SEM, and XRD, and the properties of welds were measured with MTS-810 testing system. The results show that the quantity and size of acicular Al4C3 precipitates (interfacial reaction product) decrease with the heat input decreasing. When the heat input lowers to 30 J/mm, the formation of needle-like Al4C3 can be prevented. The distributions of SiC in the fusion zones are more uniform than that in as-received composite. TEM analysis reveals that there are Al4C3 crystals on the surface of every survived particle, the needle-like Al4C3 observed under the optical microscope consists of many tabular Al4C3 crystals which have different orientations. With the increase of heat input, the fracture mechanism changes from ductile one to brittle one, the quantity of fractured particles on the fracture face decreases and the strength and ductility of the weld decrease.展开更多
In this paper the mechanism of SiC_P/LD2 aluminum matrix composites during laser welding was investigated. The emphasis was laid on the study of the distribution of aluminum carbides in whole welds. The joint can be d...In this paper the mechanism of SiC_P/LD2 aluminum matrix composites during laser welding was investigated. The emphasis was laid on the study of the distribution of aluminum carbides in whole welds. The joint can be divided into three regions both in depth and in width. The depth is divided into severe reaction region, partial reaction region, and no reaction region. In these regions, the extent of interfacial reaction varies gradually, the shape of reactants varies from long to fine. In width it can also be divided into severe reaction region, partial reaction region, and initial reaction region from the center of the weld to about the welding junction. In the initial reaction region, nucleation and growth of the reaction products on the surface of SiC particles can be observed by using TEM. The investigation showed that the quantity and size of SiC are relative to the temperature gradient in the molten pool.展开更多
文摘研究了 Si CW/L D2复合材料管材的热挤压成形工艺。研究结果表明 ,采用传统的热挤压方法得到的 Si CW/L D2复合材料管材外表面具有严重的表面缺陷 ;采用包覆挤压方法 ,可使 Si CW/L D2复合材料管材外表面覆盖一层均匀的铝包覆层 ,消除了表面缺陷 ,证明包覆挤压方法是一种有效的 Si
基金Project(2004BS05010) supported by Shandong Youth Doctoral Foundation, China
文摘The 2 mm-thick SiCp/LD2 composite plates were electron beam welded at different heat inputs. The microstructures of welds were investigated by OM, TEM, SEM, and XRD, and the properties of welds were measured with MTS-810 testing system. The results show that the quantity and size of acicular Al4C3 precipitates (interfacial reaction product) decrease with the heat input decreasing. When the heat input lowers to 30 J/mm, the formation of needle-like Al4C3 can be prevented. The distributions of SiC in the fusion zones are more uniform than that in as-received composite. TEM analysis reveals that there are Al4C3 crystals on the surface of every survived particle, the needle-like Al4C3 observed under the optical microscope consists of many tabular Al4C3 crystals which have different orientations. With the increase of heat input, the fracture mechanism changes from ductile one to brittle one, the quantity of fractured particles on the fracture face decreases and the strength and ductility of the weld decrease.
文摘In this paper the mechanism of SiC_P/LD2 aluminum matrix composites during laser welding was investigated. The emphasis was laid on the study of the distribution of aluminum carbides in whole welds. The joint can be divided into three regions both in depth and in width. The depth is divided into severe reaction region, partial reaction region, and no reaction region. In these regions, the extent of interfacial reaction varies gradually, the shape of reactants varies from long to fine. In width it can also be divided into severe reaction region, partial reaction region, and initial reaction region from the center of the weld to about the welding junction. In the initial reaction region, nucleation and growth of the reaction products on the surface of SiC particles can be observed by using TEM. The investigation showed that the quantity and size of SiC are relative to the temperature gradient in the molten pool.
