The precipitation behavior of topological close-packed（TCP）μphase in powder metallurgy（P/M）nickelbased superalloy FGH97 was investigated.The results showed that proper addition of solution strengthening elements,...The precipitation behavior of topological close-packed（TCP）μphase in powder metallurgy（P/M）nickelbased superalloy FGH97 was investigated.The results showed that proper addition of solution strengthening elements,such as Co,Cr,W,Mo,improved tensile strength,while excessive addition of those elements facilitated the precipitation ofμphase,which seriously aggravated the plasticity of the P/M superalloy.For the heat-treated specimens,the relationship between critical aging time（whenμstarted to precipitate）,aging temperature,and the average electron vacancy number ofγmatrix was established.展开更多
The three dimensional displacements fields in a surface mounted plastic quad flat pack (PQFP) assembly are measured during power cycling using a combination of holographic interferometry and high sensitivity moire int...The three dimensional displacements fields in a surface mounted plastic quad flat pack (PQFP) assembly are measured during power cycling using a combination of holographic interferometry and high sensitivity moire interferometry. Detailed in plane and out of plane whole field displacement data of the top and bottom ends of the gull wing leads and their distributions along the edge of PQFP are provided. The maximum deformations of the gull wing leads occur at the four corners of the PQFP. The experimental results are used as displacement boundary condition in a linear elastic analysis of the thermal stresses of the corner lead and its solder joint using a 3 D finite element method (FEM). The highest stresses occur in the area connecting the lead and the solder joint. The results should be useful in the evaluation of thermal fatigue damage of surface mount assemblies.展开更多
基金Item Sponsored by International Science and Technology Cooperation Program of China(2014DFR50330)
文摘The precipitation behavior of topological close-packed（TCP）μphase in powder metallurgy（P/M）nickelbased superalloy FGH97 was investigated.The results showed that proper addition of solution strengthening elements,such as Co,Cr,W,Mo,improved tensile strength,while excessive addition of those elements facilitated the precipitation ofμphase,which seriously aggravated the plasticity of the P/M superalloy.For the heat-treated specimens,the relationship between critical aging time（whenμstarted to precipitate）,aging temperature,and the average electron vacancy number ofγmatrix was established.
文摘The three dimensional displacements fields in a surface mounted plastic quad flat pack (PQFP) assembly are measured during power cycling using a combination of holographic interferometry and high sensitivity moire interferometry. Detailed in plane and out of plane whole field displacement data of the top and bottom ends of the gull wing leads and their distributions along the edge of PQFP are provided. The maximum deformations of the gull wing leads occur at the four corners of the PQFP. The experimental results are used as displacement boundary condition in a linear elastic analysis of the thermal stresses of the corner lead and its solder joint using a 3 D finite element method (FEM). The highest stresses occur in the area connecting the lead and the solder joint. The results should be useful in the evaluation of thermal fatigue damage of surface mount assemblies.
