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We propose an original route to process diamond wires, denominated In Situ Technology, whose fabrication involves mechanical conformation processes, such as rotary forging, copper tubes restacking, and thermal treatments, such as sintering and recrystallisation of a bronze 4 wt.% diamond composite. Tensile tests were performed, reaching an ultimate tensile strength (UTS) of 230 MPa for the diameter of Æ = 1.84 mm. Scanning electron microscopy showed the diamond crystals distribution along the composite rope during its manufacture, as well as the diamond adhesion to the bronze matrix. Cutting tests were carried out with the processed wire, showing a probable performance 4 times higher than the diamond sawing discs, however its probable performance was about 5 to 8 times less than the conventional diamond wires (pearl system) due to the low abrasion resistance of the bronze matrix, and low adhesion between the pair bronze-diamond due to the use of not metallised diamond single crystals.

This paper aims at showing a new route to process diamond wires, called “in situ” technology, whose fabrication involves mechanical fabrication processes such as rotary forging and wire drawing, copper tube restacking, and thermal treatments, i.e. sintering and annealing. Copper–15 vol.% Nb composite wires was used as the high tensile strength cable, covered with an external cutting rope, made of bronze 4 wt.% diamond composite, along the overall wire surface. Thus, this work shows the manufacturing route of the bronze 4 wt.% diamond composite. Tensile tests were performed, reaching an ultimate tensile strength (UTS) of 230 MPa for the rope diameter of φ=1.84 mm. Scanning electron microscopy showed the diamond crystals distribution and integrity along the composite rope during its manufacturing, as well as the diamond adhesion to the matrix. Cutting tests were carried out with the external cutting rope, presenting probable performance four times superior to diamond saws. However, the probable performance showed to be five to eight times inferior to conventional diamond wires. [Copyright &y& Elsevier]

Commercial diamond wires are cutting tools used in the slabbing of dimension stones, such as marbles and granites, as well as in the cutting of concrete structures. This kind of tool consists of an AISI 316 stainless cable on which annular diamond segments (pearls) are set up with gap between them.This work intended to design a new route to process diamond wires, called “in situ” technology, whose fabrication involves mechanical conformation process such as rotary forging and wire drawing, copper tubes restackings and thermal treatment of sintering and recrystalisation. Cu–15 vol.% Nb composite wires were used as high tensile strength cable, covered with an external cutting rope made of bronze 4 wt.% diamond composite, along the overall wire surface. Therefore, this work shows the Cu–15 vol.% Nb composite manufacturing route. Investigations on the mechanical behaviour and microstructural evolution showed an ultimate tensile strength (UTS) of 960 MPa, and strain of 2.0%. This anomalous strength increase has occurred because niobium filaments attained a ribbon like shape during processing, thus acting as barrier to copper dislocations. [Copyright &y& Elsevier]

The present study recommends sawing thin (120 μm) silicon (Si) wafers using thin (120 μm) diamond wire with higher throughputs and sawing yields (>96%). In a multi-wire saw, an improved type of diamond wire (100 d/M6-12) is employed to saw ground (g) and mirror-polished (p) Si bricks into thin (120 μm) Si wafers. Improvements in both diamond wire and Si brick surface allow us to saw thin (120 μm) Si wafers with higher fracture strengths and sawing yields of over 96%. The wafers sawn from g and p Si bricks are labeled as g- Si wafers and p- Si wafers. Depending on wire wear position, sawn wafers are labeled as fresh-wire and worn-wire sides. In a three-line bending test, mechanical loads were applied perpendicular to the wire saw marks on the middle of each wafer to measure its fracture strength. Two fundamental differences are observed in the fracture strengths of g- and p- Si wafers. The g- Si wafers fractured at lower strengths compared with the p- Si wafers. Both g- and p- Si wafers from the fresh-wire side fractured at lower strengths compared with worn-wire-side wafers. To address the fracture strength difference, edge chipping and fractographic studies were carried out. The wafer edges were observed at wire entrance and wire exit sides in the Si brick. At the wire exit side, the wafer surface contains a large number of pits followed by longer chipping lengths and widths compared with the wire entrance side. The fractographic studies were performed on fractured samples collected from the middle of the wafer by observing its cross-sections. The wafers fractured at low-strength samples follow mirror mechanisms, and the wafers fractured at intermediate- and higher-strength samples follow any one of mirror–mist, mist, hackle, branching or a mixture of these mechanisms. Image 1 • In diamond multi-wire saw, ground (g) and mirror-polished (p) silicon (Si) bricks are sawn into thin (120 μm) Si wafers using thin (120 μm) diamond wire. • The wafer sawing yield for ground (g) Si brick is over 90%, and for mirror-polished (p) Si brick is over 96%. • As sawn wafers have higher fracture strengths, we recommend that the photovoltaic industry adopt thin Si wafer-based solar cells in processing in lines in the future. [ABSTRACT FROM AUTHOR]