Small-angle neutron scattering analysis in Sn-Ag Lead-free solder alloys:A focus on the Ag₃Sn intermetallic phase

This study addresses the critical need for lead-free solder alternatives in electronic manufacturing by investigating the microstructural characteristics of Sn-Ag solder alloys, focusing on the Ag3Sn intermetallic phase. Utilizing Small-Angle Neutron Scattering (SANS), the study explored the phase interface and grain structure within Sn-Ag alloy to identify attributes that influence mechanical stability and performance. The research was structured around a comprehensive SANS analysis, complemented by Electron Backscatter Diffraction (EBSD) to expose the morphology and orientation of crystalline phases within the material. The investigation revealed distinct scattering patterns indicative of a multi-phase structure with a homogeneous distribution of fine Ag3Sn precipitates within a β-Sn matrix. EBSD data confirmed these findings, showing a wide range of grain sizes and a random orientation distribution that matches theoretical models for polycrystalline materials. Notably, the SANS data uncovered a specific size distribution of the Ag3Sn phase, which was characterized by a sharp interface contrast against the β-Sn matrix, pivotal for understanding the solder's mechanical properties. Interpretation of the SANS and EBSD data sets suggests that the Sn-Ag alloy's performance is significantly influenced by the dispersion and morphology of the Ag3Sn phase. The presence of nanoscale Ag3Sn structures, exhibiting a needle-like surface, implies a material optimized for mechanical reinforcement, which is essential for robust electronic connections. The integrated approach offers a novel perspective on the nano structural arrangement of lead-free solders, contributing to the advancement of safer, more reliable electronic materials. The findings have significant implications for the development of next-generation electronic components, reinforcing the transition to environmentally benign manufacturing processes.</p

EBSD characterization of graphene nano sheet reinforced Sn–Ag solder alloy composites

This research explores the effects of incorporating Graphene Nano Sheets (GNS) on the microstructural characteristics and mechanical behavior of Sn–Ag solder alloys. The research was driven by the need for environmentally friendly, lead-free solder alloys with enhanced mechanical and thermal properties. The methodology involved incorporating graphene into the Sn–Ag alloy through stir casting, followed by a series of surface preparation techniques. The composite samples were then examined using EBSD to analyze crystallographic orientations and SEM/EDS for surface morphology and elemental composition. XRD provided insights into phase transformations and structural changes. Key findings reveal that the addition of GNS significantly refines the grain structure of the Sn–Ag alloy, leading to a bimodal grain size distribution. This refinement is attributed to the role of GNS as a nucleation site during solidification. Moreover, the study demonstrates a pronounced alteration in the texture of the material, with an increase in low-angle grain boundaries post-GNS addition. This texture change is indicative of enhanced mechanical properties. The results also show a shift in the orientation distribution function (ODF), suggesting a stronger crystallographic orientation due to GNS. These findings suggest that GNS incorporation could lead to improved mechanical and thermal properties in Sn–Ag solder, making them suitable for high-performance electronic applications. The study concludes that GNS not only serves as an effective reinforcement in Sn–Ag solder alloys but also significantly alters their microstructural and textural characteristics, contributing to the alloy's potential application in environmentally conscious electronic manufacturing

Characterization Studies on Graphene-Aluminium Nano Composites for Aerospace Launch Vehicle External Fuel Tank Structural Application

From the aspect of exploring the alternative lightweight composite material for the aerospace launch vehicle external fuel tank structural components, the current research work studies three different grades of Aluminium alloy reinforced with varying graphene weight percentages that are processed through powder metallurgy (P/M) route. The prepared green compacts composite ingots are subjected to microwave processing (Sintering), hot extruded, and solution treated (T6). The developed Nano-graphene reinforced composite is studied further for the strength&ndash;microstructural integrity. The nature of the graphene reinforcement and its chemical existence within the composite is further studied, and it is found that hot extruded solution treated (HEST) composite exhibited low levels of carbide (Al4C3) formations, as composites processed by microwaves. Further, the samples of different grades reinforced with varying graphene percentages are subjected to mechanical characterisation tests such as the tensile test and hardness. It is found that 2 wt% graphene reinforced composites exhibited enhanced yield strength and ultimate tensile strength. Microstructural studies and fracture morphology are studied, and it is proven that composite processed via the microwave method has exhibited good ductile behaviour and promising failure mechanisms at higher load levels

Dynamic FEA Analysis of the Super Lightweight External Cryogenic Fuel Tank (SLWT) Made of Aluminium Alloy 2195–Graphene Nano Composite for Launch Vehicle Aerospace Application

This research presents a comprehensive dynamic finite element analysis (FEA) of a cryogenic fuel tank made from an innovative aluminium/lithium–graphene nano-composite material, assessing its suitability for aerospace launch vehicles carrying cryogenic hydrogen and oxygen. The study focuses on the effects of lightweighting, utilizing 0.5 wt.% reinforced graphene in the Al 2195 matrix, a material poised to revolutionize the aerospace industry. Objectives include developing a digital twin of the fuel tank, CAD modeling to aerospace standards, and conducting ANSYS simulations under launch conditions to evaluate stress, strain, and deformation. Numerical results reveal a significant weight reduction of approximately 19,420 kg and a notable maximum stress reduction of 1.3% compared to traditional Al 2195 alloy tanks. The novelty of this research lies in its pioneering analysis of aluminium/lithium–graphene composites for lightweighting in cryogenic fuel tanks under space launch conditions. Conclusions affirm the composite’s viability, advocating for the development of lighter yet robust aerospace structures and fostering innovation in spacecraft design and materials science

EBSD characterization of Ag₃Sn phase transformation in Sn–Ag lead-free solder alloys:a comparative study before and after heat treatment

The phase transformation and microstructural evolution of Sn–Ag solder alloys under heat treatment, with a focus on the Ag3Sn phase, were investigated to address the need for reliable lead-free solder alternatives in electronic packaging. Initially, the solder alloy exhibited a fine eutectic structure with well-dispersed Ag3Sn particles and a polycrystalline grain structure devoid of any strong crystallographic texture. Following heat treatment, significant microstructural changes were observed, including the coarsening of the Ag3Sn phase and the development of a preferred grain orientation, suggesting recrystallization and grain growth. XRD analysis revealed a decrease in the intensity of the Sn phase peaks and an increase in the coarseness of the Ag3Sn peaks post-heat treatment, indicating phase evolution and redistribution of silver within the alloy. The EBSD results supported the SEM findings, showing elongation and growth of grains and a shift in texture. These changes imply that heat treatment can significantly alter the mechanical properties of Sn–Ag solders, particularly affecting creep resistance and hardness due to the evolution of anisotropic mechanical properties. The study provides essential insights into the selection and optimization of solder materials for high-reliability applications in the electronics industry

Novel Machining Configuration of Carbon Fibre Reinforced Polymer (CFRP) Using Wire Electric Discharge Machining (WEDM)

Advanced aerospace materials like Carbon Fiber reinforced polymer (CFRP) contains heterogeneous and anisotropic material characteristics that does not exhibit sufficient toughness before failure. CFRP materials are recently replacing most of the modern applications like aerospace, space exploration and in various exotic engineering applications due to their outstanding strength to super lightweight properties. Manufacturing operations like cutting and machining the CFRP to the required shapes are most challenging aspects that are addressed in recent times. Aim of this research is to investigate the influence of CFRP orientation and layering pattern when machined using WEDM Machining process. As the material is extremely capable, and its heterogeneous structure makes them stand out from other conventional materials investigating its machinability using WEDM is vital. WEDM is extremely capable and could produce parts with intrinsic cuts and high precision. The various parameters involved with WEDM are carefully studied along with the novel metal-CFRP-metal sandwich configuration to machine and the CFRP samples are experimented with these parameters. The results obtained from the research are analyzed and the best suitable combinations of WEDM parameters are determined. To facilitate this, the cut samples are observed under a microscope to closely inspect the samples to discover which parameters had influenced the smoothness and quality of the cut the most.</p