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Figure 18. The work hardening of copper and copper-arsenic alloys: comparison between the data pre- sented in this article, determined for cold-hammered material, and Budd and Ottaway’s (1991) data ac- quired through cold rolling.

Figure 18 The work hardening of copper and copper-arsenic alloys: comparison between the data pre- sented in this article, determined for cold-hammered material, and Budd and Ottaway’s (1991) data ac- quired through cold rolling.

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Figure 2. Copper-arsenic phase diagram (after Subramanian and Laughlin 1988)
Figure 2. Copper-arsenic phase diagram (after Subramanian and Laughlin 1988)
Figure 3. Copper-tin phase diagram (after Scott 1991).
Figure 3. Copper-tin phase diagram (after Scott 1991).
Figure 4. Schematic. diagram locating the slabs and cylinders of metal cut from each ingot to provide test material. The surface metal shown shaded was discarded. Slab 0: used for chemical analysis by atomic absorption spectrometry; slabs 1, 2, 5, 6: 105 mil material for cold- and hot rolling; slabs 3, 4: 210 mil material for cold- and hot rolling; slab 7: material from center of ingot, used to prepare six cylinders (al, a2, bl, b2, cl, c2) for cold- and hot hammering.
Figure 4. Schematic. diagram locating the slabs and cylinders of metal cut from each ingot to provide test material. The surface metal shown shaded was discarded. Slab 0: used for chemical analysis by atomic absorption spectrometry; slabs 1, 2, 5, 6: 105 mil material for cold- and hot rolling; slabs 3, 4: 210 mil material for cold- and hot rolling; slab 7: material from center of ingot, used to prepare six cylinders (al, a2, bl, b2, cl, c2) for cold- and hot hammering.
Table 1. Composition of the experimental Cu-As and Cu-Sn ingots. The 1977-1978 analysis was carried out at Ledgemont Laboratory, Kennecott Copper Corpora- tion; the 1983 analysis was at the Central Analytical Facility, MIT.
Table 1. Composition of the experimental Cu-As and Cu-Sn ingots. The 1977-1978 analysis was carried out at Ledgemont Laboratory, Kennecott Copper Corpora- tion; the 1983 analysis was at the Central Analytical Facility, MIT.
Figure 5. Three copper-arsenic ingots (0.5, 2, and 5% As) with their hot tops still in place. The right photograph shows the highly textured surfaces that resulted from casting the alloys into a cold copper mould. The left photograph—a view from above, down onto the hot top—illustrates the considerable shrinkage of the metal during solidification (photograph by Barbara A. Wilson).
Figure 5. Three copper-arsenic ingots (0.5, 2, and 5% As) with their hot tops still in place. The right photograph shows the highly textured surfaces that resulted from casting the alloys into a cold copper mould. The left photograph—a view from above, down onto the hot top—illustrates the considerable shrinkage of the metal during solidification (photograph by Barbara A. Wilson).
Figure 6. Diagram, with dimensions, of the experimental copper-arsenic and copper-tin ingots cast to provide materials for mechanical testing.
Figure 6. Diagram, with dimensions, of the experimental copper-arsenic and copper-tin ingots cast to provide materials for mechanical testing.
Figure 7. Four as-cast copper-tin ingots with their hot tops in place: 2,5, 7, and 10% Sn (photograph by Barbara A. Wilson). ingot is small at concentrations below about 3.5 weight- percent arsenic. Figures 18 and 19 show that as-cast ingots containing between 0.5 and 2% arsenic are only minimally harder than copper: VHNcu = 50; VH Neu 2%As = 53. At an alloy concentration of 3.5% As, a-solid solution hardness increases to =~ 62 VHN, a jump of 24%. Just below the solid solubility limit, at 7% As, alloy hardness measures ~ 72 VHN, an increase of 44% over the hardness of cast copper.
Figure 7. Four as-cast copper-tin ingots with their hot tops in place: 2,5, 7, and 10% Sn (photograph by Barbara A. Wilson). ingot is small at concentrations below about 3.5 weight- percent arsenic. Figures 18 and 19 show that as-cast ingots containing between 0.5 and 2% arsenic are only minimally harder than copper: VHNcu = 50; VH Neu 2%As = 53. At an alloy concentration of 3.5% As, a-solid solution hardness increases to =~ 62 VHN, a jump of 24%. Just below the solid solubility limit, at 7% As, alloy hardness measures ~ 72 VHN, an increase of 44% over the hardness of cast copper.
Figure 8. Specifications in inches (mm) of the ASTM Rectangular Tension Subsize Test Specimen, to which all tensile test specimens were machined.
Figure 8. Specifications in inches (mm) of the ASTM Rectangular Tension Subsize Test Specimen, to which all tensile test specimens were machined.
Table 2. Comparison of changes in hardness of cold-hammered Cu-As alloys (50% reduction in thickness) as measured by the Rockwell and Vickers tests.
Table 2. Comparison of changes in hardness of cold-hammered Cu-As alloys (50% reduction in thickness) as measured by the Rockwell and Vickers tests.
Figure 9. The drop hammer-and-anvil configuration used at the GE Schenectady Metals Processing Laboratory for the cold- and hot-hammering experiments. A pair of test cylinders is positioned on the anvil prior to compression. Steel straps of varying thickness, bolted to the anvil, serve as stops to the hammer head and control the final cylinder height.
Figure 9. The drop hammer-and-anvil configuration used at the GE Schenectady Metals Processing Laboratory for the cold- and hot-hammering experiments. A pair of test cylinders is positioned on the anvil prior to compression. Steel straps of varying thickness, bolted to the anvil, serve as stops to the hammer head and control the final cylinder height.
Figure 11. The same hot-hammering sequences used to produce the arsenic bronze discs in Figure 10 were repeated in forging this series of tin bronze cylinders. The average reduction in thickness for all five alloy cylinders is 85.9%. Arrows indicate edge cracks that have propagated to the center of a disc.
Figure 11. The same hot-hammering sequences used to produce the arsenic bronze discs in Figure 10 were repeated in forging this series of tin bronze cylinders. The average reduction in thickness for all five alloy cylinders is 85.9%. Arrows indicate edge cracks that have propagated to the center of a disc.
Figure 12. Photomicrograph of a section through a Cu,0.5% As alloy cold hammered to 50% reduction in thickness. Even at this low arse- nic concentration the alloy is highly segregated, but no gamma phase has formed. Dendrites are oriented in the direction of metal flow. Mag.: 50; etchant: NH4OH + H2032.
Figure 12. Photomicrograph of a section through a Cu,0.5% As alloy cold hammered to 50% reduction in thickness. Even at this low arse- nic concentration the alloy is highly segregated, but no gamma phase has formed. Dendrites are oriented in the direction of metal flow. Mag.: 50; etchant: NH4OH + H2032.
Figure 13. Photomicrograph of a section through a Cu,3.5% As alloy cold hammered to 75% reduction in thickness. The microstructure is highly distorted, with alternating bands of copper-rich and arsenic- rich material oriented in the direction of metal flow. Deformation lines are visible in some grains, but grain boundaries have been oblit- erated. Small islands of gamma phase, homogeneously dispersed throughout the section, are present at a volume fraction of 0.7%. Mag.: 50; etchant: NH4OH + H202 + HCI.
Figure 13. Photomicrograph of a section through a Cu,3.5% As alloy cold hammered to 75% reduction in thickness. The microstructure is highly distorted, with alternating bands of copper-rich and arsenic- rich material oriented in the direction of metal flow. Deformation lines are visible in some grains, but grain boundaries have been oblit- erated. Small islands of gamma phase, homogeneously dispersed throughout the section, are present at a volume fraction of 0.7%. Mag.: 50; etchant: NH4OH + H202 + HCI.
Figure 16. Photomicrograph of a section through a Cu,10% As alloy, cold hammered to 50% reduction in thickness. The sample has been etched to bring out the eutectic microconstituent, made up of an in- termixture of alpha and gamma phase material. The gamma phase oc- cupies 25.5% of the total volume of the alloy. The high ductility and extreme elongation of this material are particularly evident along a wedge line in the section. Mag.: 100; etchant: H3PO4.
Figure 16. Photomicrograph of a section through a Cu,10% As alloy, cold hammered to 50% reduction in thickness. The sample has been etched to bring out the eutectic microconstituent, made up of an in- termixture of alpha and gamma phase material. The gamma phase oc- cupies 25.5% of the total volume of the alloy. The high ductility and extreme elongation of this material are particularly evident along a wedge line in the section. Mag.: 100; etchant: H3PO4.
Figure 14. Photomicrograph of a section through a Cu,7% As alloy cold hammered to 75% reduction in thickness. Many small islands of gamma phase make up 11% of the alloy volume. The lightly etched, closely spaced deformation lines—the result of cold work—give the microstructure a feathery appearance. Mag.: 200; etchant: NH4OH + H202 + HCl.
Figure 14. Photomicrograph of a section through a Cu,7% As alloy cold hammered to 75% reduction in thickness. Many small islands of gamma phase make up 11% of the alloy volume. The lightly etched, closely spaced deformation lines—the result of cold work—give the microstructure a feathery appearance. Mag.: 200; etchant: NH4OH + H202 + HCl.
Figure 15. A more highly magnified detail of the section shown in Figure 14. Here the section has been polished and etched lightly to reveal the islands of elongated gamma phase, strung out in the direc- tion of metal flow. Several of the larger islands exhibit an eutectic mi- crostructure. The small dark patches are pores, compressed through cold work. Mag.: 500; etchant: H3PO4.
Figure 15. A more highly magnified detail of the section shown in Figure 14. Here the section has been polished and etched lightly to reveal the islands of elongated gamma phase, strung out in the direc- tion of metal flow. Several of the larger islands exhibit an eutectic mi- crostructure. The small dark patches are pores, compressed through cold work. Mag.: 500; etchant: H3PO4.
Figure 17. A more highly magnified detail of the section shown in Figure 16. The gamma phase material is highly ductile and exhibits no cracking. Mag.: 500; etchant: H3PO4.
Figure 17. A more highly magnified detail of the section shown in Figure 16. The gamma phase material is highly ductile and exhibits no cracking. Mag.: 500; etchant: H3PO4.
* Values in parentheses are %A, the increase in hardness above that of copper, at the reduction indicated. Table 3. Work hardening of cold-hammered copper-arsenic alloys in the low arsenic range, compared with that of copper.
* Values in parentheses are %A, the increase in hardness above that of copper, at the reduction indicated. Table 3. Work hardening of cold-hammered copper-arsenic alloys in the low arsenic range, compared with that of copper.
Figure 19. The work hardening of copper and copper-arsenic alloys in the range from 0.5 to 13 weight-percent arsenic. Hardness values correspond to the resistance of the alpha and gamma phases to indentation when both phases are present.
Figure 19. The work hardening of copper and copper-arsenic alloys in the range from 0.5 to 13 weight-percent arsenic. Hardness values correspond to the resistance of the alpha and gamma phases to indentation when both phases are present.
Figure 20. Comparison of the work hardening behavior of cold-hammered copper-arsenic and copper- tin alloys as determined by the Vickers microhardness test. All alloy concentrations are given in weight percent.
Figure 20. Comparison of the work hardening behavior of cold-hammered copper-arsenic and copper- tin alloys as determined by the Vickers microhardness test. All alloy concentrations are given in weight percent.
Table 4. Ultimate tensile strength of Cu-As and Cu-Sn alloys (after Zwicker).
Table 4. Ultimate tensile strength of Cu-As and Cu-Sn alloys (after Zwicker).
Figure 21. Alloys that deform plastically when hammered work harden differently when deformed by rolling. These curves indicate that copper-arsenic alloys become slightly harder when rolled than when hammered; hardness was determined by the Rockwell B test. COPPER-ARSENIC ALLOYS, COLD ROLLED & COLD HAMMERED Hardness vs Reduction in Thickness
Figure 21. Alloys that deform plastically when hammered work harden differently when deformed by rolling. These curves indicate that copper-arsenic alloys become slightly harder when rolled than when hammered; hardness was determined by the Rockwell B test. COPPER-ARSENIC ALLOYS, COLD ROLLED & COLD HAMMERED Hardness vs Reduction in Thickness
Figure 22. The work hardening of copper-arsenic alloys is determined largely by the properties of the alpha solid solution. These curves illustrate the relatively small increase in work hardening attributable to the presence of the gamma phase.
Figure 22. The work hardening of copper-arsenic alloys is determined largely by the properties of the alpha solid solution. These curves illustrate the relatively small increase in work hardening attributable to the presence of the gamma phase.
both are reduced by 50% and is 21% stronger than pure copper upon reduction of both by 75%. The correspond- ing changes in strength, while maintaining ductility, for the Cu,1% As alloy are: 38% greater at 50% reduction and 29% greater at 75% reduction. The Cu,2% As bronze is 54%
both are reduced by 50% and is 21% stronger than pure copper upon reduction of both by 75%. The correspond- ing changes in strength, while maintaining ductility, for the Cu,1% As alloy are: 38% greater at 50% reduction and 29% greater at 75% reduction. The Cu,2% As bronze is 54%
Figure 23. Curves illustrating the principal ways of hardening metal. The cold- worked arsenic bronzes and tin bronzes were reduced in thickness by 50%. They are somewhat harder than steels that have been heated and allowed to cool naturally. Quenched steels become dramatically harder than either of the bronzes. In relation to air-cooled steels, tin bronzes are only slightly harder than arsenic bronzes (after Smith 1967: fig. 39).
Figure 23. Curves illustrating the principal ways of hardening metal. The cold- worked arsenic bronzes and tin bronzes were reduced in thickness by 50%. They are somewhat harder than steels that have been heated and allowed to cool naturally. Quenched steels become dramatically harder than either of the bronzes. In relation to air-cooled steels, tin bronzes are only slightly harder than arsenic bronzes (after Smith 1967: fig. 39).
Table 6. Elongation of tensile test specimens, cold- rolled and hot-rolled.
Table 6. Elongation of tensile test specimens, cold- rolled and hot-rolled.
Figure 25. Comparison of the work-hardening behavior of cold rolled copper-arsenic and copper-tin al- loys as determined by the Rockwell B test. All alloy concentrations are given in weight percent. COPPER-ARSENIC AND COPPER-TIN ALLOYS COLD ROLLED Hardness vs Reduction in Thickness
Figure 25. Comparison of the work-hardening behavior of cold rolled copper-arsenic and copper-tin al- loys as determined by the Rockwell B test. All alloy concentrations are given in weight percent. COPPER-ARSENIC AND COPPER-TIN ALLOYS COLD ROLLED Hardness vs Reduction in Thickness
Figure 26. The work hardening of arsenic bronzes and tin bronzes, relative to copper, as a function of the atomic percent of the alloying element.
Figure 26. The work hardening of arsenic bronzes and tin bronzes, relative to copper, as a function of the atomic percent of the alloying element.
Figure 27. The tensile strengthening of arsenic bronzes and tin bronzes, relative to copper, as a function of the atomic percent of the alloying element. RELATIVE TENSILE STRENGTHENING OF COLD ROLLED Cu-As & Cu-Sn ALLOYS vs ATOMIC PERCENT OF ALLOYING ELEMENT
Figure 27. The tensile strengthening of arsenic bronzes and tin bronzes, relative to copper, as a function of the atomic percent of the alloying element. RELATIVE TENSILE STRENGTHENING OF COLD ROLLED Cu-As & Cu-Sn ALLOYS vs ATOMIC PERCENT OF ALLOYING ELEMENT
Figure 29. Ecuadorian small axe-money, Babahoyo, Ecuador (Hosler, Lechtman, and Holm 1990: fig. 39).
Figure 29. Ecuadorian small axe-money, Babahoyo, Ecuador (Hosler, Lechtman, and Holm 1990: fig. 39).
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