Plasma arc welding was used to join SiCp/Al composite with titanium as alloying filler material. Microstructure of the weld was characterized by an optical microscope. The results show that the harmful needle-like pha...Plasma arc welding was used to join SiCp/Al composite with titanium as alloying filler material. Microstructure of the weld was characterized by an optical microscope. The results show that the harmful needle-like phase Al4C3 is completely eliminated in the weld of SiCp/Al metal matrix composite(MMC) by in-situ weld-alloying/plasma arc welding with titanium as the alloying element. The wetting property between reinforced phase and Al matrix is improved, a stable weld puddle is gotten and a novel composite-material welded joint reinforced by TiN, AlN and TiC is produced. And the tensile-strength and malleability of the welded joints are improved effectively because of the use of titanium.展开更多
The effect of Ti-Al on microstructures and mechanical properties of SiCp/Al MMC joints produced by plasma arc in-situ weld-alloying was investigated, in which argon-nitrogen mixture was used as plasma gases and Ti-Al ...The effect of Ti-Al on microstructures and mechanical properties of SiCp/Al MMC joints produced by plasma arc in-situ weld-alloying was investigated, in which argon-nitrogen mixture was used as plasma gases and Ti-Al alloy as filling composite. The results show that the formation of needle-like harmful phase Al4C3 is effectively prevented in the weld by in-situ weld-alloying/plasma arc welding with Ti-Al alloy sheet filler whose titanium content is more than 20%. The fluidity of molten pool is improved, and stable molten pool is gained for the addition of the Ti-Al alloy. The mechanical properties of welded joint are effectively enhanced by the compact-grain structure and the new reinforced composites such as Al3Ti, TiN, AlN and TiC welded joint. The test results of mechanical property show that the maximum tensile strength of welded joint gained by adding Ti-60Al alloy is up to 235 MPa. The factors influencing the tensile strength were also investigated.展开更多
Mixed Al-Si and Al-Si-SiC powders were employed as insert layers to reactive diffusion bond SiCp/6063 MMC （metal matrix composites）. The results show that SiCp/6063 MMC joints bonded by the insert layer of the mixed...Mixed Al-Si and Al-Si-SiC powders were employed as insert layers to reactive diffusion bond SiCp/6063 MMC （metal matrix composites）. The results show that SiCp/6063 MMC joints bonded by the insert layer of the mixed Al-Si powder have a dense joining layer with a typical hypoeutectic microstructtn＇e. Using the mixed Al-Si-SiC powder as the insert layer, SiCp/6063 MMC can be reactive diffusion bonded by a composite joint. Because of the SiC segregation, however, there are a number of porous zones in the joining layer, which results in the bad shear strength of the joints reactive diffusion bonded by the insert layer of the mixed A1-Si- SiC powder, even lower than that of the joints reactive diffusion bonded by the insert layer of the mixed Al-Si powder. Ti and Mg added in the insert layers obviously improve the strength of the joints reactive diffusion bonded by the insert layer of the mixed Al- Si-SiC powder, especially, Mg has a more obvious effect.展开更多
Mixed Al-Si, Al-Si-SiC and Al-Si-W powders were employed as insert layers to reactive diffusion bond SiC_p/6063 MMC. The results show that SiC_p/6063 MMC joints bonded by the insert layer of the mixed Al-Si powder hav...Mixed Al-Si, Al-Si-SiC and Al-Si-W powders were employed as insert layers to reactive diffusion bond SiC_p/6063 MMC. The results show that SiC_p/6063 MMC joints bonded by the insert layer of the mixed Al-Si powder have a dense joining layer with a typical hypoeutectic microstructure. Using mixed Al-Si-SiC powder as insert layer, SiC_p/6063 MMC can be reactive diffusion bonded by a composite joint. Because of the SiC segregations, however, there are a number of porous zones in the joining layer, which results in the low shear strength of the joints, even lower than that of joints reactive diffusion bonded by the insert layer of mixed Al-Si powder. The W added into the insert layer of Al-Si-W nearly all reacts with Al to form intermetallic WAl_ 12 during bonding. The reaction between the W and Al facilitates to form a dense joint of high quality, and the formed intermetallic WAl_ 12 has a reinforcing effect on the joints, which lead to the high shear strength of the joints. In general, under the condition of fixed bonding time (temperature), the shear strengths of the joints increase as the bonding temperature (time) increases, but tend to a maximum at bonding temperature of 600℃(time 90min).展开更多
基金Project(50475126) supported by the National Natural Science Foundation of China
文摘Plasma arc welding was used to join SiCp/Al composite with titanium as alloying filler material. Microstructure of the weld was characterized by an optical microscope. The results show that the harmful needle-like phase Al4C3 is completely eliminated in the weld of SiCp/Al metal matrix composite(MMC) by in-situ weld-alloying/plasma arc welding with titanium as the alloying element. The wetting property between reinforced phase and Al matrix is improved, a stable weld puddle is gotten and a novel composite-material welded joint reinforced by TiN, AlN and TiC is produced. And the tensile-strength and malleability of the welded joints are improved effectively because of the use of titanium.
基金Project(50475126) supported by the National Natural Science Foundation of ChinaProject(JSAWT-07-04) supported by Key Lab of Jiangsu Province for Advanced Joining Technology, China
文摘The effect of Ti-Al on microstructures and mechanical properties of SiCp/Al MMC joints produced by plasma arc in-situ weld-alloying was investigated, in which argon-nitrogen mixture was used as plasma gases and Ti-Al alloy as filling composite. The results show that the formation of needle-like harmful phase Al4C3 is effectively prevented in the weld by in-situ weld-alloying/plasma arc welding with Ti-Al alloy sheet filler whose titanium content is more than 20%. The fluidity of molten pool is improved, and stable molten pool is gained for the addition of the Ti-Al alloy. The mechanical properties of welded joint are effectively enhanced by the compact-grain structure and the new reinforced composites such as Al3Ti, TiN, AlN and TiC welded joint. The test results of mechanical property show that the maximum tensile strength of welded joint gained by adding Ti-60Al alloy is up to 235 MPa. The factors influencing the tensile strength were also investigated.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50175004)
文摘Mixed Al-Si and Al-Si-SiC powders were employed as insert layers to reactive diffusion bond SiCp/6063 MMC （metal matrix composites）. The results show that SiCp/6063 MMC joints bonded by the insert layer of the mixed Al-Si powder have a dense joining layer with a typical hypoeutectic microstructtn＇e. Using the mixed Al-Si-SiC powder as the insert layer, SiCp/6063 MMC can be reactive diffusion bonded by a composite joint. Because of the SiC segregation, however, there are a number of porous zones in the joining layer, which results in the bad shear strength of the joints reactive diffusion bonded by the insert layer of the mixed A1-Si- SiC powder, even lower than that of the joints reactive diffusion bonded by the insert layer of the mixed Al-Si powder. Ti and Mg added in the insert layers obviously improve the strength of the joints reactive diffusion bonded by the insert layer of the mixed Al- Si-SiC powder, especially, Mg has a more obvious effect.
文摘Mixed Al-Si, Al-Si-SiC and Al-Si-W powders were employed as insert layers to reactive diffusion bond SiC_p/6063 MMC. The results show that SiC_p/6063 MMC joints bonded by the insert layer of the mixed Al-Si powder have a dense joining layer with a typical hypoeutectic microstructure. Using mixed Al-Si-SiC powder as insert layer, SiC_p/6063 MMC can be reactive diffusion bonded by a composite joint. Because of the SiC segregations, however, there are a number of porous zones in the joining layer, which results in the low shear strength of the joints, even lower than that of joints reactive diffusion bonded by the insert layer of mixed Al-Si powder. The W added into the insert layer of Al-Si-W nearly all reacts with Al to form intermetallic WAl_ 12 during bonding. The reaction between the W and Al facilitates to form a dense joint of high quality, and the formed intermetallic WAl_ 12 has a reinforcing effect on the joints, which lead to the high shear strength of the joints. In general, under the condition of fixed bonding time (temperature), the shear strengths of the joints increase as the bonding temperature (time) increases, but tend to a maximum at bonding temperature of 600℃(time 90min).
