Microstructural and mechanical characterization of 10 vol% SiC particles (SiCp) reinforced 6061 Al-based composite fabricated by powder thixoforming (PTF) was investigated in comparison with the PTF and permanent mold cast (PMC) 6061 monolithic alloys. The results reveal that the microstructure of the PMC alloy consists of coarse and equiaxed α dendrites and interdendritic net-like eutectic pha...

We present here the findings of Alpha’s Alloy Development Program on the next generation of low temperature alloys that can be used in reflow soldering temperatures from 170 to 200C. Approaches in alloy development, test methodologies and results are discussed. The alloy properties targeted for improvements include: Alloy strength, alloy ductility, microstructure stability, improvements in ther...

In the present study, M2 high speed steels were fabricated by using electro-slag rapid remelting process. Carbide structure was analysed and the fracture toughness and hardness were also measured after austenitization treatment at 1190 and 1210C followed by tempering treatment at 535C for billets with various diameters from 16 to 60 mm. Electro-slag rapid remelting (ESRR) process is an advanced...

A feasibility study of the partial squeeze and vacuum die casting process was performed to make defect-free casting products with excellent mechanical properties. The trial die casting process in this study was industrially implemented for producing a reaction shaft support made of a hyper eutectic Al±15%Si alloy. To combine the squeezing and vacuum effect, the plunger injection system was desi...

The microsegregation behavior of electron beam (EB, and gas tungsten arc (GTA) welds of Al-Cu alloys covering a range from 0.19 to 7.74 wt% Cu were characterized for dendrite core concentrations and fraction eutectic solidification. Although a single weld speed of 12.7 mm/sec was used, some differences were observed in the segregation behavior of the two weld types. The microsegregation behavio...

A program has been conducted on the effects of Mg in cast alloy 718. The results show that small amounts of Mg improves impact toughness and decreases Nb segregation by decreasing secondary dendrite arm spacing which results in less and smaller interdendritic Laves and MC eutectics. Small amounts of Mg produce a more spheroidal as well as a more dispersive MC phase. Impact toughness was found t...

Sn-Pb eutectic solder alloy is extensively used in microelectronics packaging interconnects. Due to the high homologous temperature, eutectic Sn-Pb solder exhibits creepfatigue interaction and significant time-, temperature-, stress-, and rate-dependent material characteristics. The microstructure is often unstable, having significant effects on the flow behavior of solder joints at high homolo...

We present adaptive finite element simulations of dendritic and eutectic solidification in binary and ternary alloys. The computations are based on a recently formulated phase-field model that is especially appropriate for modelling non-isothermal solidification in multicomponent multiphase systems. In this approach, a set of governing equations for the phase-field variables, for the concentrat...

Low temperature, Sn-based Pb-free solders were developed by making alloy additions to the starting material, 96.5Sn-3.5Ag (mass%). The melting behavior was determined using Differential Scanning Calorimetry (DSC). The solder microstructure was evaluated by optical microscopy and electron probe microanalysis (EPMA). Shear strength measurements, hardness tests, intermetallic compound (IMC) layer ...

As the second part to a paper presented at the 2004 SMTA Pan Pacific Symposium, this paper further summarizes the results from technical qualification of the Ni/Pd/Au process. Whereas the previous paper examined the wire bonding capabilities of this surface finish, this second paper focuses specific attention to BGA applications. In these investigations, the solder joint integrity is measured u...