Ahmad Badri Ismail

Characteristic of low temperature of Bi-In-Sn solder alloy

Due to the increase in the use of electronics devices within the industry, the usage of solder connections has increased. These is a concern that lead within the electronic products is considered toxic because lead has potential for leaching from landfills onto water sources and becoming a hazard to human health and surrounding environment. For this reason, replacing Sn-37Pb to free solder with low melting temperature is one of the most important issues in electronic industry. This is due to a demand on low temperature for interconnection and polymer based part component such as LCD display functionality availability at low temperature apply. In this paper, Bi-In-Sn system alloy was investigated as a potential candidate replacing Sn-37Pb. This study covers on solder characteristic such as melting temperature, thermal expansion and microstructure. Bi-In-Sn was prepared and melted in crucible. Solder was cleaned mechanical and chemical before characterized. DSC shows that, Bi-In-Sn system alloy give low melting temperature in range of 65-100°C. The addition of In to Bi-Sn system alloy lowered the melting temperature compared than Sn-37Pb. Lowest melting temperature ensures that the solder melts, forms a joint with the substrates, and re-solidifies within the shortest possible process time. From thermal expansion analysis, it was found that Bi-In-Sn gives good expansion properties to avoid mismatch between Cu pads and solder itself. EDX analysis indicated that, there are two obvious regions in Bi-In-Sn system alloy microstructure. Bright colour refers to BiIn rich phase region and dark colour refers to Sn rich phase region. BiIn rich phase region is higher compared to Sn rich phase in solder give good properties in terms of ductility.

Conventional cold-rolling and annealing of 0.06%C steel

This paper demonstrated the ability to obtain an ultrafine-grained microstructure in 0.06%C steel via a simple process of cold-rolling and annealing, without the need for a severe plastic deformation process. A dual-phase ferrite-martensite starting microstructure was cold-rolled by 75% reduction in thickness and subsequently annealed at various temperatures from 400°C to 700°C for 30 min. The microstructures, as well as the microhardness and tensile strength properties, were evaluated by metallographic analyses and mechanical tests, respectively. The results showed that the specimen annealed at an intermediate temperature of 500°C exhibited excellent mechanical properties when compared to other annealing temperatures, as well as the as-received specimen.

Effect of Rolling Reduction on Microstructure and Mechanical Properties of Plain Low Carbon Steel

In the present study, the effect of cold-rolling for the amount of reduction in thickness ranging from 25% to 75% on microstructure and mechanical properties of plain low carbon steel processed from dual-phase ferrite-martensite starting microstructure was studied. As the cold-rolling, the microstructure elongated to rolling direction and more compressed with increasing the rolling reduction and strength also increased. After annealing at warm temperature 500°C, the ultrafine grained was obtained in the 75% rolling reduction. Moreover, it was exhibited excellent strength of 82% and hardness of 66.1% higher than as-received condition with adequate uniform elongation 9.6%.

Development of WILMS: Well Inform Landslide Monitoring System for USM Healthy Campus

Slope monitoring system was installed for the purpose of monitoring the hill development for student accommodation which houses three main blocks of hostels. This was implemented under a special programme known as Healthy Campus which covers all aspects conducive to student, staff and environment. A full package of pilot study has been conducted by a group of experts in the field to run a monitoring and mitigation system for Universiti Sains Malaysia (USM) hostels. WILMS (Well-Inform Landslides Monitoring System) is a real-time web monitoring system which integrates the use of SMS (Short Messaging Services) and MMS (Multimedia Messaging Services) technology to inform and to alert users of different needs about the presence of a pessimistic change in land stability. The uniqueness of this application is that it makes monitoring job easier, without needing constant human power while maintaining accurate data acquisition cocpyntinuously and reducing human errors. This method is offering cheaper solution as well as sustaining environmental issues.

Responses of Aging Treatment to the Behavior of Aluminum Alloy with Addition of 0.02% Zirconium Element

Response of aging treatment on aluminum alloy towards its hardness has been investigated. Alloy used on this research was develop base on a US patent 4121951 that is use to produce aluminum cable with excellent strength and conductivity [1]. Solutioninzing treatment was carried out to the alloy at 520 °C for 2 hours. Alloy then were artificial aged at 180 °C, 200 °C and 220 °C for various periods up to 10 hours. Natural aging also has been carried out for 2 weeks right after solution quenching. By referring to the results, hardness increase as the aging time increase until it reaches the maximum peak and then decreases as the result of overaging. Hardness of artificial aged alloy then was compared with 99.99% pure aluminum, as-cast and naturally aged alloy. Alloy aged at 180 °C for 2 hours give the highest value of hardness which is 34.26 Hv followed by naturally aged alloy and pure aluminum with 30.92 Hv and 15.2 Hv. The effect of different time of artificial aging gives significant change in hardness in order to improve the strength of aluminum alloy. Minor addition of zirconium during the aluminum processing will probably cause by the precipitation of Zr particles towards the aluminum matrix [2], thus increase the strength even these particulate cannot be detected by XRD. These particles will retard the grain movement and also stable upon heating due the low solubility of zirconium in aluminum matrix.

Effect of Deformation Behavior on the Grain Size of the 6061 Aluminum Alloy Joint with Alumina by Friction Welding

Friction welding is widely used as a mass-production method in various industries. Joining of ceramic-metal is one of the most essential needs of many industrial applications. Experiments were performed to observe the deformation characteristics of 6061 aluminum alloy after joining with alumina using friction-welding process at different rotational speeds and to relate difference in grain size with differences in deformation behavior. In the present study, electron microscopy and X-ray diffraction profile analysis were used to study the effect of plastic deformation of interface material on the grain size of 6061 aluminum alloy when there is a joint with the ceramic. The effect of rotation speed and the degree of deformation appeared to be high on the 6061 Al alloy than on the ceramic part. Results showed different deformation mechanisms at different rotational speeds and confirmed unambiguously the change in crystalline grains as a result of deformation mechanisms.

Effects of Sb on SnAgCu lead-free solder

This research work investigates the effect of 0.5 wt%, 1.0 wt% and 1.5 wt% Sb addition in 96.8 wt% Sn 2.5 wt% Ag 0.7 wt% Cu. Addition of Sb has shown significant effect on metallography, wettability (using ZnCl2 as flux), thermal properties as well as mechanical properties of the SnAgCu solder. The wettability test has been carried out using Cu as substrate by varying the solder temperature. A good wettability profile has been obtained at 280°C. Differential scanning calorimetry and thermogravimetric analysis have been performed on the solders to determine the melting temperature, melting behaviour and thermal stability of the solders. Results show that Sb addition has not reduced the melting temperature of SnAgCu. The solders show no significant weight loss after heating up to 300°C. Tensile and shear tests have been carried out on soldered copper substrates and all of the solders tested show a ductile fracture mode. The strength of the solder joint is actually a competition in between the ductility of the solder and also the percentage of voids formed in the joint.