Development of new multicomponent Sn–Ag–Cu–Bi lead-free solders for low-cost commercial electronic assembly

Influence of Ce addition on Sn-3.0Ag-0.5Cu solder joints: Thermal behavior, microstructure and mechanical properties

The main problem with ceramics used in cutting tools is related to the unpredictable failures caused by the brittle fracturing of ceramic inserts, which is critical for the intermittent milling of cyclic loading. A 125-mm-diameter eight-toothed end mill, with a mechanical fastening of ceramic inserts, was used as a cutting tool for milling hardened steel (102Cr6). For the experiments, square inserts of the Al2O3 + SiC ceramic were used and compared with the samples made of Al2O3 + TiC to confirm the obtained results. The samples were coated with diamond-like coating (DLC), TiZrN, and TiCrAlN coatings, and their bending strength and adhesion were investigated. Investigations into the friction coefficient of the samples and operational tests were also carried out. The effect of smoothing the microroughness and surface defects in comparison with uncoated inserts, which are characteristic of the abrasive processing of ceramics, was investigated and analyzed. The process developed by the authors of the coating process allows for the cleaning and activation of the surface of ceramic inserts using high-energy gas atoms. The impact of these particles on the cutting edge of the insert ensures its sharpening and reduces the radius of curvature of its cutting edges.

https://www.mdpi.com/2079-6412/8/8/287/pdf

The Role of Thin-Film Vacuum-Plasma Coatings and Their Influence on the Efficiency of Ceramic Cutting Inserts

This paper investigates the influence of adding nickel (Ni) nanoparticles on the microstructure, wettability and material properties of Sn–35Bi–1Ag (wt%) based solders. Material properties such as elastic and shear moduli, stress/strain behavior and electrical resistivity of bulk composite solder were improved significantly in comparison to the corresponding properties of reference solder alloy. The elastic and shear moduli of composite solder increased about 16.8 and 19 % respectively, while the electrical resistivity at room temperature was improved from 23.7 to 25.1 μΩ cm. On the other hand, in solder joint on Cu substrate, an island-shaped Cu6Sn5 IMC layer was clearly observed at interface for the plain solder/substrate system. Further a prolong reaction, a very thin Cu3Sn IMC layer was also formed at the substrate surface. However, in the case of the composite solder/substrate system, a scallop-shaped ternary (Cu, Ni)–Sn IMC layer was observed to be adhered at the interface without formation of Cu3Sn IMC layer for the composite solder/substrate system. Moreover, the composite solder/substrate system hindered the growth behavior of IMC layer as well as refined the microstructure which can influence life-span of electronic devices. Additionally, the overall micro-hardness values of composite solder joints exhibited higher values as compare to the plain solder joints due to the second phase strengthening mechanism.

Interfacial microstructure, wettability and material properties of nickel (Ni) nanoparticle doped tin–bismuth–silver (Sn–Bi–Ag) solder on copper (Cu) substrate

Sn-0.7 wt%Cu-(xNi) alloys: Microstructure-mechanical properties correlations with solder/substrate interfacial heat transfer coefficient

In the present work, the effect of Ce concentration on microstructure refinement, melting behavior and mechanical properties of a series of near-eutectic Sn–Ag–Cu alloys have been investigated. Twelve different alloys with Ce concentration between 0.005 and 0.171 wt% were prepared by melting of the pure elements in high purity argon, followed by quenching to room temperature. The samples microstructure and phase constitution were investigated by a combination of light microscopy, scanning electron microscopy, X-ray diffraction, and energy dispersive X-ray spectroscopy. In the alloys a total of five different phases have been identified: β-Sn, Cu 6 Sn 5 , Ag 3 Sn, CeO 2 , and CeSn 3 . The Ce addition is found to contribute to the refinement of mostly eutectic microstructures. The CeO 2 and/or CeSn 3 phases are observed in alloys with high Ce concentration. The absence of these particles in alloys with low Ce concentration (0.005–0.011 wt%) shows a complete dissolution of Ce in the β-Sn solid solution. The elongation and ultimate tensile strength of the alloys were determined under a constant strain rate of 2 mm min −1 . Moreover, the toughness (i.e. specific fracture energy) was calculated from the area underneath the force–extension curve. Melting temperatures are found to change slightly with bulk Ce concentration. Solution strengthening by Ce atoms, grain refinement, and the stress concentration along both types of Ce-rich particles of undesirable shapes are considered to be the main factors influencing the mechanical properties of the investigated alloy systems.

Influence of cerium addition on microstructure and properties of Sn–Cu–(Ag) solder alloys

Purpose – The purpose of this paper is to study the effect of the addition of a small amount of Al (01 percent) on the properties of lead‐free solder type Sn‐4Ag‐05Cu (SAC 405)Design/methodology/approach – The soldering properties of wettability and spreadability on a Cu substrate were studied, and the effect of Al on the growth of intermetallic compounds (IMCs) was observed The shear strength of soldered joints was assessed For comparison, soldering and strength tests were carried out on SAC 405 and SAC 405+ Al solders Soldering was performed with an activated flux type ZnCl2‐NH4Cl, with non‐activated flux (rosin), and without flux in the airFindings – Experimental results show that Al addition slightly reduces the wettability and spreadability of SAC 405 solder Also, the shear strength is moderately reduced, dropping by 8 MPa on average Differential scanning calorimetry (DSC) analysis showed that the melting point of SAC 405+01%Al solder was increased to 221°COriginality/value – The positive 

Comparison study of SAC405 and SAC405+0.1%Al lead free solders

In this article, the effect of process parameters on the microstructure and mechanical properties of AW5083 aluminum alloy weld joints welded by a disk laser were studied. Butt welds were produced using 5087 (AlMg4.5MnZr) filler wire, with a diameter of 1.2 mm, and were protected from the ambient atmosphere by a mixture of argon and 30 vol.% of helium (Aluline He30). The widest weld joint (4.69 mm) and the highest tensile strength (309 MPa) were observed when a 30 L/min shielding gas flow rate was used. Conversely, the narrowest weld joint (4.15 mm) and the lowest tensile strength (160 MPa) were found when no shielding gas was used. The lowest average microhardness (55.4 HV0.1) was recorded when a 30 L/min shielding gas flow rate was used. The highest average microhardness (63.9 HV0.1) was observed when no shielding gas was used. In addition to the intermetallic compounds, β-Al3Mg2 and γ-Al12Mg17, in the inter-dendritic areas of the fusion zone (FZ), Al49Mg32, which has an irregular shape, was recorded. The application of the filler wire, which contains zirconium, resulted in grain refinement in the fusion zone. The protected weld joint was characterized by a ductile fracture in the base material (BM). A brittle fracture of the unshielded weld joint was caused by the presence of Al2O3 particles. The research results show that we achieved the optimal welding parameters, because no cracks and pores were present in the shielded weld metal (WM).

https://www.mdpi.com/2075-4701/10/11/1443/pdf

The Effect of Process Parameters on the Microstructure and Mechanical Properties of AW5083 Aluminum Laser Weld Joints

Local plastic deformation in cutting zone during turning is affected by technological conditions of the processes. Therefore it is needful to know detail structure changes of plastic deformed material during machining. It is localised, asymmetric deformation which operates at very large strains and exceptionally high strain rates. Three areas of intensive local plastic deformation in cutting zone were observed: the primary area of plastic deformation in shear plane, the secondary area of plastic deformation caused by friction of chip to tool face and the tertiary area of plastic deformation caused by friction of tool to machined surface. Local strain in these three areas was estimated by measurement of deformation of grains on metallographic cut. The effect of grains boundaries self-orientation caused by grains deformation was evaluated using stereology. But the orientation is not the same as deformation and so a correlation between the grain deformation and grain orientation was used. The turning piece was made of CK45 (1.0503) carbon steel. The specimen of cutting zone was obtained by using internal stress method.

Estimation of Local Plastic Deformation in Cutting Zone during Turning

Abstract The purpose of this article is to describe the methodology to define coefficient of friction between a tool and a forming material during tube cold draw technology process. In this regard, an experimental drawing process was done by using the tensile testing machine. The tensile testing machine was modified by additional equipment that allows drawing the tube. During the drawing, the force was recorded. Subsequently, the finite element simulation of cold draw forming was used to generate load-stroke curves with different friction coefficient. The friction coefficient was estimated by comparing the load stroke and the force recorded curves.

/pdf/determination-of-the-coefficient-of-friction-under-cold-tube-40n08zodwe.pdf

Maroš Martinkovič

Papers

Influence of cerium addition on microstructure and properties of Sn–Cu–(Ag) solder alloys

Comparison study of SAC405 and SAC405+0.1%Al lead free solders

The Effect of Process Parameters on the Microstructure and Mechanical Properties of AW5083 Aluminum Laser Weld Joints

Estimation of Local Plastic Deformation in Cutting Zone during Turning

Determination of the Coefficient of Friction Under Cold Tube Drawing Using FEM Simulation and Drawing Force Measurement