Processing technology for improving quality and microscopic structure of gold-based alloy melt

Abstract

The invention discloses a processing technology for improving the quality and microstructure of a gold-based alloy melt, the microstructure of a gold-based alloy can be effectively improved by using a method for treating the alloy by using pulse current, and the method controls the second phase precipitation and the microstructure size of the gold-based alloy. Compared with a traditional gold-based alloy machining method, the technology for improving the alloy microscopic structure through the pulse current is simple, meanwhile, the alloy with the uniform structure and the reduced hard and brittle phases can be obtained during pulse current modification, follow-up machining treatment is facilitated, and the toughness and machinability of the gold-based alloy are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of material preparation and processing, and in particular to a processing technology for improving the quality and microstructure of a gold-based alloy melt. Background Art

[0002] Gold, a precious metal, holds broad application prospects in a variety of fields, including precision resistor materials, electrical contact materials, solders, and electroplating materials. However, gold-based alloys, such as gold-tin and gold-germanium, face numerous challenges during their preparation and processing. Extensive inhalation of gases from the melt and the subsequent coarse, dendritic formation of the solidified primary phase lead to a significant reduction in the mechanical properties of the material. This directly impacts the practical efficiency of gold-based alloys in industrial production. To improve the mechanical properties of gold-based alloys, researchers have begun exploring the possibility of adding other elements. For example, the addition of nickel not only slightly reduces the lattice parameter of the face-centered cubic single-phase solid solution but, more importantly, effectively reduces work hardening and improves the mechanical properties of the material. This discovery provides new insights into the production and development of gold-based alloys. However, while the addition of microalloying elements can improve the processing properties of gold-based alloys and increase product yield, it can also alter the physical properties of the alloy, thereby affecting functional properties such as electrical conductivity and wettability.

[0003] Therefore, the present invention introduces a pulse current during the smelting process, which, on the one hand, discharges the dissolved gas by stirring the melt, and on the other hand, destroys the dendrites of the primary phase to achieve the effect of refining the structure, thereby improving the plastic forming performance, tensile strength and yield rate of the alloy without changing its thermophysical properties. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention designs a processing technology for improving the quality and microstructure of gold-based alloy melt by using a method of modifying the microstructure of gold-germanium-nickel alloy by pulse current.

[0005] In order to achieve the above technical effects, the present invention is implemented through the following technical solutions: A processing technology for improving the quality and microstructure of a gold-based alloy melt, characterized in that it includes the following steps:

[0006] S1: The gold-based alloy is heated and melted in a melting furnace, then naturally cooled for degassing and slag removal, and finally cast to obtain a cast alloy;

[0007] S2: annealing the obtained cast alloy and cutting it into block alloys with a size of 20 cm × 10 cm;

[0008] S3: The obtained bulk alloy is modified by a pulse current processing method, and finally a gold-germanium-nickel alloy with uniform structure and small size is obtained.

[0009] Furthermore, in S1, the gold-based alloy includes a gold-tin system (gold-tin-nickel alloy) and a gold-germanium system (gold-germanium-nickel alloy), wherein the tin content of the gold-tin system is 1 wt% to 20 wt%, the nickel content is 0.5 wt% to 1 wt%, and the remainder of the Au in the alloy is 79 wt% to 98.5 wt%. The germanium content of the gold-germanium system is 1 wt% to 20 wt%, the nickel content is 0.5 wt% to 1 wt%, and the remainder of the Au in the alloy is 79 wt% to 98.5 wt%.

[0010] Furthermore, in S2, the temperature of the natural cooling for degassing and slag removal is 380-420°C, and the casting temperature is 360-380°C.

[0011] Furthermore, in S2, the annealing treatment temperature is 180-220° C., and the holding time is 24 hours.

[0012] Furthermore, in S3, the current density of the pulse current is 100 to 900 A / mm 2 , the pulse frequency is 1 to 100 Hz, the pulse width is 1 to 100 μm, and the processing time is 10 to 60 s.

[0013] The beneficial effects of the present invention are:

[0014] 1. The present invention adopts rheo-die casting to prepare the as-cast gold-based alloy, and the subsequent annealing treatment makes the as-cast structure uniform, providing a good foundation for subsequent processing;

[0015] 2. The present invention utilizes a pulsed current modification method to improve the microstructure of gold-based alloys. After the pulsed current modification, the alloy is naturally cooled to approximately 340°C. Argon, an inert gas, is then introduced to cool and solidify the alloy. Because the pulsed current bombardment regulates the precipitated phases, the precipitation of hard and brittle phases is reduced, and the grain size is improved. Compared to gold-based alloys obtained using previous processing techniques, the resulting gold-based alloy exhibits significantly improved toughness and tensile strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 It is a process flow chart of the present invention;

[0018] Figure 2 The microstructure of the as-cast Au-Ge-Ni alloy of the present invention;

[0019] Figure 3 This is the Au-Ge-Ni alloy microstructure in Example 4 of the present invention. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0021] Example 1

[0022] A processing technology for improving the quality and microstructure of gold-based alloy melt is as follows:

[0023] In this embodiment, a gold-germanium-nickel alloy is first heated to 1000°C in a smelting furnace to melt, then naturally cooled to 400°C for degassing and slag removal, and then naturally cooled to 370°C for casting. The resulting alloy is then annealed and cut into blocks of 20×10 (cm). The resulting block alloy is then subjected to pulse current modification at a current density of 100A / mm 2 , the pulse frequency is 10 Hz, the pulse width is 10 μm, the processing time is 10 s, and then the inert gas - argon is introduced for cooling and solidification to obtain the gold-germanium-nickel alloy.

[0024] Example 2

[0025] A processing technology for improving the quality and microstructure of gold-based alloy melt is as follows:

[0026] In this embodiment, a gold-germanium-nickel alloy is first heated to 1000°C in a smelting furnace to melt, then naturally cooled to 400°C for degassing and slag removal, and then naturally cooled to 370°C for casting. The resulting alloy is then annealed and cut into blocks of 20×10 (cm). The resulting block alloy is then subjected to pulse current modification at a current density of 300A / mm 2 , the pulse frequency is 30 Hz, the pulse width is 30 μm, the processing time is 20 s, and then the inert gas - argon is introduced for cooling and solidification to obtain the gold-germanium-nickel alloy.

[0027] Example 3

[0028] A processing technology for improving the quality and microstructure of gold-based alloy melt is as follows:

[0029] In this embodiment, a gold-germanium-nickel alloy is first heated to 1000°C in a smelting furnace to melt, then naturally cooled to 400°C for degassing and slag removal, and then naturally cooled to 370°C for casting. The resulting alloy is then annealed and cut into blocks of 20×10 (cm). The resulting block alloy is then subjected to pulse current modification at a current density of 500A / mm. 2 , the pulse frequency is 50 Hz, the pulse width is 50 μm, the processing time is 30 s, and then the inert gas - argon is introduced for cooling and solidification to obtain the gold-germanium-nickel alloy.

[0030] Example 4

[0031] A processing technology for improving the quality and microstructure of gold-based alloy melt is as follows:

[0032] In this example, a gold-germanium-nickel alloy was first heated to 1000°C in a smelting furnace to melt, then naturally cooled to 400°C for degassing and slag removal, and then naturally cooled to 370°C for casting. The resulting alloy was then annealed and cut into blocks of 20×10 (cm). The resulting block alloy was then subjected to pulse current modification at a current density of 700A / mm. 2 , the pulse frequency is 70 Hz, the pulse width is 70 μm, the processing time is 40 s, and then the inert gas - argon is introduced for cooling and solidification to obtain the gold-germanium-nickel alloy.

[0033] Example 5

[0034] A processing technology for improving the quality and microstructure of gold-based alloy melt is as follows:

[0035] In this embodiment, a gold-germanium-nickel alloy is first heated to 1000°C in a smelting furnace to melt, then naturally cooled to 400°C for degassing and slag removal, and then naturally cooled to 370°C for casting. The resulting alloy is then annealed and cut into blocks of 20×10 (cm). The resulting block alloy is then subjected to pulse current modification at a current density of 900A / mm. 2 , the pulse frequency is 90 Hz, the pulse width is 90 μm, the processing time is 50 s, and then the inert gas - argon is introduced for cooling and solidification to obtain the gold-germanium-nickel alloy.

[0036] Based on the above examples 1-5, the current density of the pulse current is 700A / mm 2 The gold-germanium-nickel alloy with the best microstructure can be obtained when the pulse frequency is 70 Hz, the pulse width is 70 μm and the processing time is 40 s.

[0037] Furthermore, in the present invention, the addition of Ni to the gold-germanium alloy slightly reduces the lattice parameter of the fcc solid solution, which can reduce work hardening. During alloy casting, a lower casting temperature facilitates the removal of coarse dendrites. During pulse current modification, a suitable current density can directly regulate phase transformation by influencing grain boundary energy or atomic bonding states. A suitable pulse frequency is suitable for regulating recrystallization throughout the alloy, effectively improving microstructural uniformity. Appropriate pulse width and treatment time can achieve a homogenized microstructure.

[0038] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all details in detail, nor do they limit the invention to only the specific implementation methods described.

Claims

1. A processing technology for improving the quality and microstructure of a gold-based alloy melt, characterized in that: The following steps are involved: S1: The gold-based alloy is heated and melted in a melting furnace, then naturally cooled for degassing and slag removal, and finally cast to obtain a cast alloy; S2: annealing the obtained cast alloy and cutting it into block alloys with a size of 20 cm × 10 cm; S3: The obtained bulk alloy is modified by a pulse current processing method, and finally a gold-germanium-nickel alloy with uniform structure and small size is obtained.

2. A processing technology for improving the quality and microstructure of a gold-based alloy melt according to claim 1, characterized in that: In S1, the gold-based alloy includes a gold-tin system (gold-tin-nickel alloy) and a gold-germanium system (gold-germanium-nickel alloy), wherein the tin content of the gold-tin system is 1 wt% to 20 wt%, the nickel content is 0.5 wt% to 1 wt%, and the balance of Au in the alloy is 79 wt% to 98.5 wt%. The germanium content of the gold-germanium system is 1 wt% to 20 wt%, the nickel content is 0.5 wt% to 1 wt%, and the balance of Au in the alloy is 79 wt% to 98.5 wt%.

3. A processing technology for improving the quality and microstructure of a gold-based alloy melt according to claim 1, characterized in that: In S2, the temperature of the natural cooling for degassing and slag removal is 380-420°C, and the temperature of the casting is 360-380°C.

4. A processing technology for improving the quality and microstructure of a gold-based alloy melt according to claim 1, characterized in that: In S2, the annealing treatment temperature is 180-220° C., and the holding time is 24 hours.

5. A processing technology for improving the quality and microstructure of a gold-based alloy melt according to claim 1, characterized in that: In S3, the current density of the pulse current is 100~900A / mm 2 , the pulse frequency is 1 to 100 Hz, the pulse width is 1 to 100 μm, and the processing time is 10 to 60 s.

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