WO2022216083A1 - Aluminum alloy for die casting thin-walled products and electronic device - Google Patents

Abstract

According to various embodiments, an aluminum alloy for die casting thin-walled products may comprise, with respect to the total weight of the alloy, 9.0-11.0 wt% of silicon (Si), 1.0-1.3 wt% of magnesium (Mg), 0.0001-0.9 wt% of iron (Fe), 0.0001 wt% or greater and less than 0.1 wt% of copper (Cu), greater than 2.0 wt% and 3.0 wt% or less of zinc (Zn), an amount of strontium (Sr) satisfying the Sr content ratio to follow, and the balance of aluminum (Al), wherein the Sr content ratio may be in the range of (wt% of Si - 1.74 x wt% of Mg):wt% of Sr = 200–1,000:1. Various other embodiments may be possible.

Description

Aluminum alloys and electronic devices for thin-walled die casting

Various embodiments of the present invention relate to an aluminum alloy for die-casting thin products and an electronic device including a component manufactured therewith.

Thin products cast using die casting, particularly parts mounted on mobile electronic devices, must be able to maintain their original shape by resisting external impact. It is usually evaluated as an index of yield strength, impact resistance, etc., and various methods for imparting these properties to die-casting products are being studied.

Attempts have been made to apply aluminum alloys for general die casting to thin-walled products. For example, Al-Si-based alloys such as ADC10 and ADC12 having a high Si content are used to obtain high fluidity required for filling thin products to improve castability. However, these alloys have difficulty in securing durability of thin-walled products because their impact resistance is reduced due to lack of toughness.

There is an attempt to combine Mg-based alloys to overcome the above toughness degradation problem. However, elements added to secure rigidity and supplement anti-seismic properties in die-casting alloys make it difficult to avoid corrosion. In particular, when the alloy for die casting is applied to parts of electronic devices such as mobile phones, it is important to prevent corrosion in the use environment of the electronic devices. However, the conventional aluminum alloy for die casting suffers from difficulties in mass-production application due to poor fluidity, toughness, and corrosion resistance due to a lack of technical understanding of the overall die casting process of thin-walled products.

On the other hand, in order to secure mechanical properties, the production of thin-walled products through the forging method has been attempted. However, this method has limitations in manufacturing products with complex shapes, and in particular, additional machining is required to form products with protrusions such as bosses. Therefore, this method cannot meet the modern product production trend that requires various appearances at low cost.

In order to minimize defects occurring when an aluminum alloy is die-casting to cast a thin product, the Si content may be increased in the composition of the aluminum alloy. However, commercial Al-Si alloys lack toughness and are easily corroded. For example, ADC10, which is the most used alloy for die casting, has a high Si content, so it can secure fluidity and has excellent machinability by adding Cu. It falls off and is easily corroded in a corrosive environment, so it is not suitable for the application of exterior materials.

In addition, metal elements such as Mg and Zn may be added to the aluminum alloy for die casting in order to secure the rigidity of the thin product. However, when such a metal element is added, the elongation tends to decrease. For example, AZ91D, which is an Mg-based alloy used for die casting, has high specific strength and excellent electromagnetic shielding performance, so it is widely used as a material for mobile communication terminals. However, there is a problem in product application due to the difficulty in managing the molten metal and the complexity of various treatments to obtain a good-quality outer layer of the injection-molded product. In addition, the problem of hot cracking, which is represented by fracture and internal shrinkage pore generation due to shrinkage stress during product solidification, corrosion resistance problem in which the appearance is easily oxidized in a corrosive environment, insufficient fluidity problem due to low latent heat emission compared to Al-Si alloys, etc. It has a problem with thin die-casting injection molding.

Therefore, it is necessary to provide a composition and content range of an aluminum alloy for die casting thin products to simultaneously satisfy high fluidity/crack resistance, yield strength and toughness, and corrosion resistance in a corrosive environment suitable for filling thin products.

According to various embodiments of the present disclosure, it is possible to provide an aluminum alloy for die-casting thin products that simultaneously satisfy high fluidity, high toughness, and high corrosion resistance, a thin-walled component manufactured therefrom, and an electronic device including the component.

According to various embodiments, the aluminum alloy for die-casting of thin-walled products, with respect to the total weight of the alloy, 9.0 wt% or more and 11.0 wt% or less of silicon (Si), 1.0 wt% or more and 1.3 wt% or less of magnesium (Mg), 0.0001 wt% or more and 0.9 wt% or less of iron (Fe), 0.0001 wt% or more and less than 0.1 wt% of copper (Cu), more than 2.0 wt% and 3.0 wt% or less of zinc (Zn), and the following strontium (Sr) content ratio strontium (Sr) in an amount satisfying It can be in the range of ~1000:1.

According to various embodiments, the electronic device component may be made of the aluminum alloy for die casting of the thin product.

According to various embodiments, the electronic device may include the electronic device component.

Various embodiments of the present invention can provide an aluminum alloy for die casting of thin products with improved fluidity, toughness and corrosion resistance as well as suitable for die casting by using an aluminum alloy containing silicon and a specific metal element in a specific ratio. In addition, since the thin part made of the aluminum alloy for die casting of the thin product is flexible, strong against external impact, and does not corrode well, it may be applied to at least one of a front plate, a back plate, and a support plate included in a mobile electronic device. Among them, in particular, it can be excellently applied to a bracket, which is a thin-walled part having a complex shape while being disposed as a support plate inside an electronic device and adjacent to a front plate, display, printed circuit board, battery, etc., thereby providing a durable and safe electronic device. can In addition, various effects directly or indirectly identified through this document may be provided.

In connection with the description of the drawings, the same or similar reference numerals may be used for the same or similar components.

1 shows the shape of casting defects and hot cracks of an aluminum alloy (Comparative Example 2-1) according to a comparative example of the present invention.

FIG. 2 shows a comparison of microstructures of an aluminum alloy according to an embodiment of the present invention (Example 1) and an aluminum alloy according to a comparative example (Comparative Example 2-3).

Figure 3a shows the corrosion resistance evaluation results of the aluminum alloy (Example 1) and the aluminum alloy (Comparative Example 1, Comparative Example 4-1, Comparative Example 4-2) according to the comparative example according to an embodiment of the present invention. Figure 3b shows the corrosion resistance evaluation results of the aluminum alloy (Example 3) and the aluminum alloy (Comparative Example 1) according to the comparative example according to the embodiment of the present invention.

4 is a perspective view of a front side of a mobile electronic device according to various embodiments of the present disclosure;

5 is a perspective view of a rear surface of the electronic device of FIG. 4 according to various embodiments of the present disclosure;

6 is an exploded perspective view of the electronic device of FIG. 4 according to various embodiments of the present disclosure;

Hereinafter, the present invention will be described in detail with reference to the drawings.

Aluminum alloy for die casting thin products

According to various embodiments of the present invention, the aluminum alloy for die-casting of thin-walled products is, based on the total weight of the alloy, 9.0 wt% or more and 11.0 wt% or less of silicon (Si), 1.0 wt% or more and 1.3 wt% or less of magnesium ( Mg), 0.0001 wt% or more and 0.9 wt% or less iron (Fe), 0.0001 wt% or more and less than 0.1 wt% copper (Cu), more than 2.0 wt% and 3.0 wt% or less zinc (Zn), strontium (Sr) strontium (Sr) in an amount that satisfies the content ratio of strontium (Sr), and the remaining amount of aluminum (Al), and the content ratio of strontium (Sr) is (weight% of Si - 1.74 x weight% of Mg): weight of Sr % = 200 to 1000: may be in the range of 1.

According to one embodiment, the aluminum alloy for die casting thin products contains 9.0 wt% or more and 11.0 wt% or less, preferably 10.2 wt% or more and 10.7 wt% or less of silicon (Si), based on the total weight of the alloy. can When the alloy contains silicon in the above amount, latent heat is increased and liquidus is lowered, so that castability of the alloy can be improved, and hot cracks, which are shrinkage defects during solidification, can be prevented. In addition, when the primary crystal is dissolved, Mg ₂ Si is generated in the primary crystal together with magnesium to increase the strength of the thin product. When the alloy contains less than 9.0% by weight of silicon, hot cracks occur at the weak flow portion during solidification during die casting of the thin product, and it is difficult to obtain sufficient fluidity in the final filling portion. When the alloy contains more than 11.0 wt % of silicon, segregation is generated in the process, and supercrystalline silicon is crystallized from the segregation portion to lower the toughness and workability of the thin product.

According to one embodiment, the aluminum alloy for die-casting thin products contains 1.0 wt% or more and 1.3 wt% or less, preferably 1.05 wt% or more and 1.25 wt% or less of magnesium (Mg), based on the total weight of the alloy. can When the alloy contains magnesium in the above amount, it is possible to secure strength suitable for thin-walled products by solid solution in the aluminum primary crystal and hardening. In addition, as the content of magnesium in the alloy increases within the content range, the strength of the alloy increases. Magnesium forms Mg ₂ Si in the primary crystal together with silicon, and when the Mg:Si ratio is 1.74, Mg ₂ Si at the maximum solid solution level in the primary crystal may be produced. When the ratio of Mg:Si exceeds 1.74, Mg exceeding the solid solution in the primary crystal is crystallized in the process region as Mg ₂ Si phase. As the ratio of Mg: Si increases, the strength and hardness of the material increase but toughness decreases do. When the alloy contains less than 1.0% by weight of magnesium, it is difficult to secure strength suitable for thin products. When the alloy contains more than 1.3 wt % of magnesium, Mg ₂ Si is excessively produced and also causes segregation, thereby lowering elongation.

According to one embodiment, the aluminum alloy for die-casting thin products contains 0.0001 wt% or more and 0.9 wt% or less, preferably 0.0001 wt% or more and 0.2 wt% or less iron (Fe), based on the total weight of the alloy. can When the alloy contains iron in the above amount, mold burning can be alleviated. When the alloy contains less than 0.0001 wt% of iron, the effect of improving the sintering may not appear. When the alloy contains more than 0.9 wt % of iron, as the content increases, a β-Al ₅ FeSi phase appears and elongation is greatly reduced, and oxidation occurs due to activation in a corrosive environment.

According to one embodiment, the aluminum alloy for thin-walled product die-casting, based on the total weight of the alloy, contains 0.0001% by weight or more and less than 0.1% by weight, preferably 0.0001% by weight or more and 0.005% by weight or less of copper (Cu). can When the alloy contains copper in the above amount, strength suitable for thin-walled products can be secured by solid solution and hardening of the precipitate. When the alloy contains copper in an amount of 0.1 wt% or more, intermetallic compounds are generated in the process to cause segregation, and do not have sufficient corrosion resistance in a corrosive environment.

According to one embodiment, the aluminum alloy for die-casting of thin-walled products may contain more than 2.0% by weight and not more than 3.0% by weight, preferably more than 2.0% by weight and not more than 2.5% by weight of zinc (Zn), based on the total weight of the alloy. can When the alloy contains zinc in the above amount, a reinforcing effect is exhibited within the solid solution range in the Al primary crystal, and sufficient rigidity can be obtained. When the alloy contains 2.0 wt% or less of zinc, the effect of increasing the stiffness is insignificant, and when the alloy contains more than 3.0 wt%, corrosion resistance is deteriorated due to the compound precipitated without being dissolved in solid solution during casting.

According to an embodiment, the aluminum alloy for die casting thin products may contain strontium (Sr) in an amount satisfying the following strontium (Sr) content ratio with respect to the total weight of the alloy. The content ratio of strontium (Sr) may be in the range of (weight% of Si - 1.74 × weight% of Mg): weight% of Sr = 200 to 1000: 1, preferably in the range of 300 to 500: 1. can When the alloy contains strontium in the above range, it is possible to improve the rigidity and elongation of the thin product. In the alloy, strontium may serve as an eutectic Si modifier. Si improvement treatment consists of the reaction of Si and strontium remaining after the reaction with magnesium, and the amount of remaining Si is the amount of Si remaining after generating the Mg ₂ Si compound. 1.74 times the weight of Mg in the weight of Si added to the alloy It is the amount of Si minus the value. When the alloy does not contain strontium within the above range, silicon that has not been treated with strontium is crystallized into needles, and under impact conditions, stress is concentrated on the tip of the needles, which causes easy fracture, and elongation of thin products is reduced. . When the alloy contains too much strontium out of the above range, the cost of the material increases, and the remaining strontium generates unnecessary compounds, thereby reducing physical properties.

According to an embodiment, the aluminum alloy for die casting thin products may contain nickel (Ni) of 0.0001 wt % or more and 0.01 wt % or less based on the total weight of the alloy. Nickel in the alloy may serve to secure tensile properties in a high-temperature environment. Nickel has an allergic reaction to the human body, and in particular, in Europe, it is limited as an environmentally harmful substance, so the content of Ni is limited to the above range in the present invention.

According to an embodiment, the aluminum alloy for die casting thin products may contain manganese (Mn) of 0.0001 wt% or more and 0.25 wt% or less based on the total weight of the alloy. When the alloy contains manganese in the above amount, it is dissolved in Al primary crystal to have a strengthening effect, and it is possible to improve the tensile and yield strength of a thin product even in a non-heat treatment environment. In addition, by changing the β-Al ₅ FeSi phase to the α-AL(FeMn)Si phase, it is possible to improve the elongation and improve the sintering properties. When the alloy contains less than 0.0001 weight % of manganese, the strength improvement is insignificant, and when it contains more than 0.25 weight % of manganese, segregation occurs and elongation of thin products is reduced.

According to an embodiment, the aluminum alloy for die casting thin products may contain 0.35 wt% or more and 0.5 wt% or less of chromium (Cr) based on the total weight of the alloy. When the alloy contains chromium in the above amount, strength can be improved through solid solution in the primary crystal. When the alloy contains less than 0.35% by weight of chromium, the strength improvement effect is small, and when the alloy contains more than 0.5% by weight of chromium, more than chromium dissolved in the primary crystal is crystallized in the process, thereby lowering the corrosion resistance.

According to one embodiment, the aluminum alloy for die casting thin products may contain 0.17 wt% or more and 0.25 wt% or less of titanium (Ti) based on the total weight of the alloy. In the alloy, titanium may act as an effective element for grain reinforcement. When the alloy contains titanium in the above amount, it can act as a nucleation site due to a scavenger reaction with Al, and can prevent hot cracks by refining the particles. In addition, the primary crystallized titanium plays a role of dispersion strengthening, and may act to increase the physical properties of the thin product, particularly the hardness. When the alloy contains less than 0.17% by weight of titanium, the increase in hardness is not sufficient. In addition, since titanium is an element with very little solid solution with Al, when the alloy contains more than 0.25 wt% of titanium, an additional refining effect cannot be obtained, and segregation occurs to impair the uniformity of thin products.

According to an embodiment, the alloy may contain tin (Sn) in an amount of 0.015 wt% or more and 0.035 wt% or less in addition to the silicon or metal elements. When the alloy contains tin in the above amount, changes in low-temperature aging can be suppressed, thereby suppressing changes in physical properties during natural aging at room temperature. When the alloy contains less than 0.015% by weight of tin, there is little effect of inhibiting aging, and when the alloy contains more than 0.035% by weight of tin, it is difficult to expect an additional effect.

According to one embodiment, the alloy is more preferably, based on the total weight of the alloy, 10.2 wt% or more and 10.7 wt% or less of silicon (Si), 1.05 wt% or more and 1.25 wt% or less of magnesium (Mg), 0.0001 wt% or more and 0.9 wt% or less of iron (Fe), 0.0001 wt% or more and 0.005 wt% or less of copper (Cu), more than 2.0 wt% and 2.5 wt% or less of zinc (Zn), and the following strontium (Sr) content ratio strontium (Sr) in an amount satisfying Titanium (Ti) in weight % or more and 0.25 wt% or less, tin (Sn) in 0.015 wt% or more and 0.035 wt% or less, and the remaining amount of aluminum (Al), and the content of strontium (Sr) is (Si Weight % - 1.74 × weight % of Mg): weight % of Sr = 300-500: It may be in the range of 1.

According to an embodiment, the aluminum alloy for die casting thin products may have a yield strength of 210 MPa or more, and an elongation of 2% or more.

When the thin-walled product, particularly the exterior or interior material of a mobile electronic device such as a mobile phone, has low yield strength and low elongation, impact resistance is lowered, thereby causing damage to a frame and an internal display when falling. For example, in a mobile electronic device, a bracket, which is a thin component adjacent to a battery, needs to have minimal permanent deformation in order to prevent problems such as bending or disconnection of the battery. For this purpose, the yield strength and elongation of the aluminum alloy for die casting of thin products need to be within the above ranges.

If the yield strength of the alloy is 210 MPa or more, permanent deformation of the thin-walled product is minimized, thereby providing an electronic device that is strong against external impact and is safe.

If the elongation of the alloy is 2% or more, casting defects occurring during die casting may be prevented, and flexibility suitable for components of mobile electronic devices may be provided.

Hereinafter, the aluminum alloy for die-casting thin products according to the present invention will be described in more detail through preferred embodiments.

Fabrication of aluminum alloy for thin-walled die casting

Example samples and comparative example samples having the compositions shown in Table 1 were prepared according to a conventional aluminum alloy production method (unit: wt%).

Examples 1 to 3 are samples included within the range of the aluminum alloy composition for die casting thin products according to the present invention. Comparative Example 1 is a sample corresponding to the composition of ADC10, which is an aluminum alloy for commercial die casting. Comparative Examples 2-1, 2-2, 2-3 and 2-4 are samples in which the content of Si, Mg or Sr is outside the range of the alloy composition according to the present invention. Comparative Examples 3-1 and 3-2 are samples in which the Mg content is outside the range of the alloy composition according to the present invention. Comparative Examples 4-1 and 4-2 are samples in which the content of Fe, Zn, or Cu is outside the range of the alloy composition according to the present invention.

	Si	Mg	Fe	Mn	Zn	Cu	Ni	Cr	Sn	Ti	Sr	Al
Example 1	10.52	1.08	0.15	0.09	2.10	0.003	0.008	0.41	0.032	0.195	0.019	remaining amount
Example 2	10.52	1.21	0.18	0.11	2.09	0.003	0.008	0.41	0.021	0.164	0.023	remaining amount
Example 3	10.61	1.18	0.81	0.10	2.12	0.002	0.007	0.40	0.024	0.184	0.021	remaining amount
Comparative Example 1	8.15	0.19	0.93	0.21	2.29	3.284	0.868	0.05	0.018	0.035	0.000	remaining amount
Comparative Example 2-1	7.51	0.75	0.18	0.09	2.15	0.011	0.009	0.41	0.024	0.205	0.010	remaining amount
Comparative Example 2-2	8.69	0.82	0.18	0.09	2.13	0.008	0.009	0.39	0.024	0.202	0.009	remaining amount
Comparative Example 2-3	10.57	0.83	0.20	0.09	2.17	0.008	0.009	0.40	0.025	0.199	0.006	remaining amount
Comparative Example 2-4	13.24	0.84	0.19	0.07	2.12	0.009	0.008	0.37	0.024	0.211	0.005	remaining amount
Comparative Example 3-1	10.56	0.87	0.14	0.09	2.10	0.009	0.008	0.40	0.031	0.195	0.027	remaining amount
Comparative Example 3-2	10.81	1.45	0.20	0.08	2.09	0.007	0.008	0.41	0.023	0.177	0.021	remaining amount
Comparative Example 4-1	10.63	1.29	0.34	0.10	2.32	0.378	0.014	0.40	0.024	0.168	0.010	remaining amount
Comparative Example 4-2	10.52	1.26	0.38	0.11	4.41	0.007	0.008	0.41	0.021	0.174	0.018	remaining amount

Evaluation of castability and hot cracking of aluminum alloy for thin-walled die casting

The weight of the filled part of the thin plate part and the chill vent part was compared according to the material composition. In addition, Comparative Example 1, which is a material of ADC 10 that is commonly used for die casting due to its high fluidity, was used as a fluidity evaluation standard. The results of castability and hot cracking according to the alloy composition are shown in FIGS. 1 and 2 .

1 shows the casting defects of the specimen of Comparative Example 2-1 and the shape of cracks appearing during solidification of the thin plate. Referring to FIG. 1 , it can be seen that Comparative Example 2-1 exhibits significant casting defects such as shrinkage defects, pore defects, non-formation, and hot cracks in thin parts, and thus is not suitable for casting thin products.

Table 2 shows the results of castability evaluation (thin filling amount and fluidity) and hot crack generation for Example 1 and Comparative Examples 2-1 to 2-4 of the present invention.

	Composition (some excerpts)			Castability evaluation		Hot crack generation (%)
	Si (weight%)	Mg (weight%)	Cu (weight%)	Thin filling amount (g)	ADC10 Contrast Fluidity (%)
Example 1	10.52	1.08	0.003	30.5	98.7	0 (0/20)
Comparative Example 1	8.15	0.19	3.284	30.9	-	20 (4/20)
Comparative Example 2-1	7.51	0.75	0.011	28.9	93.5	45 (9/20)
Comparative Example 2-2	8.69	0.82	0.008	30	97	30 (6/20)
Comparative Example 2-3	10.57	0.83	0.008	30.8	99.6	0 (0/20)
Comparative Example 2-4	13.24	0.84	0.009	31.9	103.2	0 (0/20)

As shown in Table 2, as the amount of Si added in Example 1 and Comparative Examples 2-1 to 2-4 of the present invention increases within the range of 7.5 to 13.5 wt%, the thin filling amount of the alloy tends to increase. It was. In addition, the filling amount showed a tendency to be dominated by Si, and when the amount of Si added was 10 wt % or more, it showed filling properties similar to Comparative Example 1 used as a commercial die-casting material. In addition, such filling properties were not significantly changed even when the Mg content was changed. In particular, in the case of Comparative Examples 2-1 and 2-2 in which the Si content is smaller than that of Examples, it can be seen that the occurrence of hot cracks is large. In addition, in Comparative Examples 2-1 and 2-2, there is little compensation for shrinkage through Si during solidification and lack of fluidity when filling thin-walled products, so the residual liquid having the process composition is filled, and in this part, the tension due to shrinkage The inventors speculate that cracks are easily generated.

Evaluation of mechanical properties of aluminum alloys for thin-walled die casting

Examples 1 to 2 and Comparative Examples 2-3, Comparative Example 2-4, Comparative Example 3-1, Comparative Example 3-2 of the present invention were subjected to tensile evaluation and drop test, and the results are shown in Fig. 2 and Table 3. The falling weight test is an evaluation to check whether fracture or compression occurs in the cast material by dropping a 500 g weight from 50 cm to a plate-shaped cast material of 0.4T.

	Composition (some excerpts)				mechanical properties			fall test
	Si (weight%)	Mg (weight%)	Sr (weight%)	Sr index	Yield strength (Mpa)	elongation (%)	Hardness (HV)
Example 1	10.52	1.08	0.019	455	213.4	2.52	125.9	No cracks
Example 2	10.52	1.21	0.023	366	215.6	2.14	127.7	No cracks
Comparative Example 2-3	10.57	0.83	0.006	1521	197.9	0.93	110.1	Minor dents/fractures
Comparative Example 2-4	13.24	0.84	0.005	2356	221.9	0.75	141.1	fall test break
Comparative Example 3-1	10.56	0.87	0.027	335	191.9	3.25	108.1	Fall test pressed
Comparative Example 3-2	10.81	1.45	0.021	395	224.6	1.54	138.7	fall test break

* Sr index: ratio of effective Sr = (wt% of Si - 1.74 x wt% of Mg) / wt% of Sr

Thin products, particularly mobile electronic devices, such as mobile phones, have low yield strength and low elongation, and thus have low impact resistance, which may cause damage to frames and internal displays when dropped.

As shown in Table 3, the Example alloy (Example 1) according to the present invention exhibits high elongation and yield strength at the same time as compared to the alloy of Comparative Example.

On the other hand, when the addition amount of Si exceeds 11% as in Comparative Example 2-4, it has a composition close to the eutectic point of the Al-Si binary alloy. A very light primary Si phase can be locally crystallized. This may cause tissue instability and local hardness difference, and in particular, greatly impede the elongation of the material, making it vulnerable to impact, so it is difficult to apply to thin-walled exterior products.

In addition, in Example 1, which was made within the alloy composition range according to the present invention by increasing the addition amount of Sr, the yield strength was increased and the elongation was improved at the same time as compared to Comparative Example 2-3.

In Comparative Example 3-1 in which the amount of Mg added was less than the alloy composition range according to the present invention and Comparative Example 3-2 exceeding this, the elongation and strength were low, and the content of Sr was the content of Sr suggested in the present invention. , that is, (weight % of Si - 1.74 × weight % of Mg): even if the weight % of Sr = 200 to 1000 : 1 (Table 3 indicates the content of Sr as the Sr index), the amount of Mg is When the content is less than 1.0%, pressing occurs due to low rigidity, and when the amount of Mg exceeds 1.3%, the amount of Mg ₂ Si is excessively generated, resulting in microcracks and fractures during the actual falling weight test.

2 is a view showing a comparison of the microstructure of Example 1 Comparative Example 2-3 of the present invention in order to compare the difference according to the presence or absence of Sr addition. Referring to FIG. 2, in the case of Example 1, due to the addition of Sr within the alloy composition range according to the present invention, the shape of eutectic Si was improved from a needle shape to a short rod shape, and it can be seen that the length was also reduced. This may cause initial fracture due to stress concentration at the tip of acicular Si when an external impact is applied to the alloy in which Si is added in large amounts, but the inventors speculate that the stress concentration point is removed by adding Sr and elongation is increased.

Evaluation of corrosion resistance of aluminum alloys for thin-walled die casting

Salt spray evaluation was performed on Examples 1 and 3 and Comparative Example 1, Comparative Example 4-1, and Comparative Example 4-2 of the present invention. The results are shown in Figures 3a, 3b and Table 4.

	Composition (some excerpts, wt%)				Salt Spray Results
	Si	Fe	Cu	Zn
Example 1	10.52	0.15	0.003	2.1	No corrosion
Example 3	10.61	0.81	0.002	2.12	No corrosion
Comparative Example 1	8.15	0.93	3.284	2.29	A lot of corrosion
Comparative Example 4-1	10.63	0.34	0.378	2.32	corrosion occurs
Comparative Example 4-2	10.52	0.38	0.007	4.41	Small amount of corrosion

As shown in Figures 3a, 3b and Table 4, it can be seen that when the addition amount of Fe, Cu, Zn in the alloy is within the range of a typical die-casting material as in Comparative Example 1, the corrosion resistance is rapidly reduced. Comparative Example 4-1 and Comparative Example 4-2 show that when the amount of Fe, Cu, or Zn added is higher than the composition range of the alloy according to the present invention, sufficient corrosion resistance cannot be secured. On the other hand, Example 1 showed excellent corrosion resistance because corrosion did not occur in a salt water environment even though the amount of Si added was higher than that of Comparative Example 1, and Example 3 had a Fe content similar to Comparative Example 1, but the content of Cu and Zn When this is low, it shows that it has excellent corrosion resistance.

components for electronic devices

According to various embodiments, a component for an electronic device made of the aluminum alloy for die casting of the thin product may be provided. The thin part made of the aluminum alloy for die-casting of the thin-walled product may have characteristics that are flexible, strong against external impact, and do not easily corrode.

According to an embodiment, the electronic device component may be an interior material or an exterior material of the mobile electronic device. The part for the electronic device may be a thin part of a mobile electronic device having a particularly complex shape.

Referring to FIG. 6 , according to an embodiment, the electronic device component may be at least one of a front plate 320 , a rear plate 380 , and a first support plate 311 constituting the electronic device 300 . have.

According to an embodiment, the electronic device component may be the first support plate 311 . According to an embodiment, the first support plate may be a bracket, which is a thin component having a complex shape while adjacent to the front plate 320 , the display 101 , the printed circuit board 340 , the battery 350 , and the like. When the first support plate is disposed adjacent to the battery 350 in the electronic device because permanent deformation is minimized, bending or disconnection of the battery may be prevented.

electronic device

According to various embodiments, an electronic device including the electronic device component may be provided.

4 is a perspective view of the front of the mobile electronic device 100 according to various embodiments of the present disclosure. 5 is a perspective view of a rear surface of the electronic device 100 of FIG. 4 according to various embodiments of the present disclosure.

Referring to FIGS. 4 and 5 , the electronic device 100 according to an embodiment includes a first surface (or front surface) 110A, a second surface (or rear surface) 110B, and a first surface 110A. and a housing 110 including a side surface 110C surrounding the space between the second surfaces 110B. In another embodiment (not shown), the housing may refer to a structure forming a part of the first surface 110A, the second surface 110B, and the side surface 110C of FIG. 4 . According to one embodiment, the first surface 110A may be formed by the front plate 102 (eg, a glass plate including various coating layers, or a polymer plate) at least a portion of which is substantially transparent. The second surface 110B may be formed by the substantially opaque back plate 111 . The back plate 111 is formed by, for example, coated or colored glass, ceramic, polymer, metal (eg, aluminum, stainless steel (STS), or magnesium), or a combination of at least two of the above materials. can be The side surface 110C is coupled to the front plate 102 and the rear plate 111 and may be formed by a side bezel structure 118 (or "side member") including a metal and/or a polymer. In some embodiments, the back plate 111 and the side bezel structure 118 are integrally formed and may include the same material (eg, a metal material such as aluminum).

In the illustrated embodiment, the front plate 102 has a first region 110D that extends seamlessly by bending from the first surface 110A toward the rear plate, a long edge of the front plate. edge) can be included at both ends. In the illustrated embodiment (refer to FIG. 5), the rear plate 111 may include a second region 110E that extends seamlessly from the second surface 110B toward the front plate at both ends of the long edge. have. In some embodiments, the front plate 102 or the back plate 111 may include only one of the first region 110D or the second region 110E. In some embodiments, the front plate 102 may not include the first region and the second region, but only a flat plane disposed parallel to the second surface 110B. In the above embodiments, when viewed from the side of the electronic device, the side bezel structure 118 has a first thickness ( or width), and may have a second thickness thinner than the first thickness at the side surface including the first area or the second area.

According to an embodiment, the electronic device 100 includes the display 101 , the input device 103 , the sound output devices 107 and 114 , the sensor modules 104 and 119 , and the camera modules 105 , 112 , 113 . , a key input device 117 , an indicator (not shown), and at least one of connectors 108 and 109 . In some embodiments, the electronic device 100 may omit at least one of the components (eg, the key input device 117 or an indicator) or additionally include other components.

The display 101 may be exposed through a substantial portion of the front plate 102 , for example. In some embodiments, at least a portion of the display 101 may be exposed through the front plate 102 forming the first area 110D of the first surface 110A and the side surface 110C. The display 101 may be disposed adjacent to or coupled to a touch sensing circuit, a pressure sensor capable of measuring the intensity (pressure) of a touch, and/or a digitizer that detects a magnetic field type stylus pen. In some embodiments, at least a portion of the sensor module 104 , 119 , and/or at least a portion of a key input device 117 is located in the first area 110D and/or the second area 110E. can be placed.

The input device 103 may include a microphone 103 . In some embodiments, the input device 103 may include a plurality of microphones 103 arranged to sense the direction of the sound. The sound output devices 107 and 114 may include speakers 107 and 114 . The speakers 107 and 114 may include an external speaker 107 and a receiver 114 for calls. In some embodiments, the microphone 103 , the speakers 107 , 114 , and the connectors 108 , 109 are disposed in the space of the electronic device 100 , and externally through at least one hole formed in the housing 110 . may be exposed to the environment. In some embodiments, the hole formed in the housing 110 may be commonly used for the microphone 103 and the speakers 107 and 114 . In some embodiments, the sound output devices 107 and 114 may include a speaker (eg, a piezo speaker) that operates while excluding a hole formed in the housing 110 .

The sensor modules 104 and 119 may generate electrical signals or data values corresponding to an internal operating state of the electronic device 100 or an external environmental state. The sensor modules 104 and 119 include, for example, a first sensor module 104 (eg, a proximity sensor) and/or a second sensor module (not shown) disposed on the first surface 110A of the housing 110 . ) (eg, a fingerprint sensor), and/or a third sensor module 119 (eg, an HRM sensor) disposed on the second surface 110B of the housing 110 . The fingerprint sensor may be disposed on the first surface 110A (eg, the home key button 115 ) of the housing 110 , a partial region of the second surface 110B, or under the display 101 . The electronic device 100 includes a sensor module not shown, for example, a gesture sensor, a gyro sensor, a barometric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a color sensor, an IR (infrared) sensor, a biometric sensor, a temperature sensor, It may further include at least one of a humidity sensor and an illuminance sensor 104 .

The camera modules 105 , 112 , and 113 include a first camera device 105 disposed on the first surface 110A of the electronic device 100 , and a second camera device 112 disposed on the second surface 110B of the electronic device 100 . ), and/or a flash 113 . The camera modules 105 and 112 may include one or more lenses, an image sensor, and/or an image signal processor. The flash 113 may include, for example, a light emitting diode or a xenon lamp. In some embodiments, two or more lenses (a wide-angle lens, an ultra-wide-angle lens, or a telephoto lens) and image sensors may be disposed on one surface of the electronic device 100 .

The key input device 117 may be disposed on the side surface 110C of the housing 110 . In another embodiment, the electronic device 100 may not include some or all of the above-mentioned key input devices 117 and the not included key input devices 117 are displayed on the display 101 as soft keys or the like. It may be implemented in other forms. In another embodiment, the key input device 117 may be implemented using a pressure sensor included in the display 101 .

The indicator may be disposed, for example, on the first surface 110A of the housing 110 . The indicator may provide, for example, state information of the electronic device 100 in the form of light. In another embodiment, the light emitting device may provide, for example, a light source that is interlocked with the operation of the camera module 105 . Indicators may include, for example, LEDs, IR LEDs and xenon lamps.

The connector holes 108 and 109 include a first connector hole 108 capable of receiving a connector (eg, a USB connector) for transmitting and receiving power and/or data to and from an external electronic device, and/or an external electronic device. and a second connector hole (or earphone jack) 109 capable of accommodating a connector for transmitting and receiving audio signals.

Some of the camera modules 105 and 112 , some of the camera modules 105 , some of the sensor modules 104 and 119 , or some of the sensor modules 104 or indicators may be disposed to be exposed through the display 101 . For example, the camera module 105 , the sensor module 104 , or the indicator may be in contact with the external environment through a through hole drilled from the internal space of the electronic device 100 to the front plate 102 of the display 101 . can be placed. In another embodiment, some sensor modules 104 may be arranged to perform their functions without being visually exposed through the front plate 102 in the internal space of the electronic device. For example, in this case, the area of the display 101 facing the sensor module may not need a through hole.

6 is an exploded perspective view of the electronic device 100 of FIG. 4 according to various embodiments of the present disclosure.

The electronic device 300 of FIG. 6 may be at least partially similar to the electronic device 100 of FIGS. 4 and 5 , or may include another embodiment of the electronic device.

Referring to FIG. 6 , the electronic device 300 (eg, the electronic device 100 of FIG. 4 or 5 ) includes a side frame 310 (eg, a side bezel structure or side member), a first support plate ( 311) (eg, a bracket or support structure), a front plate 320 (eg, a front cover), a display 330 , a printed circuit board 340 , a battery 350 , a second support plate 360 (eg: rear case), an antenna 370 , and a rear plate 380 (eg, a rear cover). In some embodiments, the electronic device 300 may omit at least one of the components (eg, the first support plate 311 or the second support plate 360 ) or additionally include other components. . At least one of the components of the electronic device 300 may be the same as or similar to at least one of the components of the electronic device 100 of FIG. 4 or 5 , and overlapping descriptions will be omitted below.

The first support plate 311 may be disposed inside the electronic device 300 and connected to the side frame 310 , or may be integrally formed with the side frame 310 . The first support plate 311 may be formed of, for example, a metal material and/or a non-metal (eg, polymer) material. The first support plate 311 may have a display 330 coupled to one surface and a printed circuit board 340 coupled to the other surface. The printed circuit board 340 may be equipped with a processor, memory, and/or an interface. The processor may include, for example, one or more of a central processing unit, an application processor, a graphics processing unit, an image signal processor, a sensor hub processor, or a communication processor.

Memory may include, for example, volatile memory or non-volatile memory.

The interface may include, for example, a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, an SD card interface, and/or an audio interface. The interface may, for example, electrically or physically connect the electronic device 300 to an external electronic device, and may include a USB connector, an SD card/MMC connector, or an audio connector.

The battery 350 is a device for supplying power to at least one component of the electronic device 300 and may include, for example, a non-rechargeable primary battery, a rechargeable secondary battery, or a fuel cell. . At least a portion of the battery 350 may be disposed substantially on the same plane as the printed circuit board 340 . The battery 350 may be integrally disposed inside the electronic device 300 . In another embodiment, the battery 350 may be detachably disposed from the electronic device 300 .

The antenna 370 may be disposed between the rear plate 380 and the battery 350 . The antenna 370 may include, for example, a near field communication (NFC) antenna, a wireless charging antenna, and/or a magnetic secure transmission (MST) antenna. The antenna 370 may, for example, perform short-range communication with an external device or wirelessly transmit/receive power required for charging. In another embodiment, the antenna structure may be formed by a part of the side bezel structure 310 and/or the first support plate 311 or a combination thereof.

According to various embodiments, the first support plate 311 of the side frame 310 may have a first surface 3101 facing the front plate 320 and a direction opposite to the first surface 3101 (eg, a rear plate direction). and a second surface 3102 facing toward According to an embodiment, the camera module 400 (eg, the camera module 105 of FIG. 4 ) may be disposed between the first support plate 311 and the rear plate 380 . According to one embodiment, the camera module 400 is directed to the front plate 320 through the first through hole 301 connected from the first surface 3101 to the second surface 3102 of the first support plate 311 . It may be arranged to protrude or be exposed. According to one embodiment, the portion protruding through the first through hole 301 of the camera module 400 is the front plate 320 through the second through hole 331 formed at a corresponding position of the display 330 . It may be arranged to be adjacent to or in contact with the rear surface of the . In another embodiment, when the camera module 400 is disposed between the display 330 and the first support plate 311 , the first through hole 301 may be unnecessary. In another embodiment, when the camera module 400 is disposed between the display 330 and the first support plate 311 , the second through hole 331 formed in the display 330 (eg, a display panel) is may be unnecessary. In this case, the corresponding area of the display 330 (eg, a display panel) corresponding to the camera module 400 may be formed as an area having relatively higher transmittance than the surrounding area by rearranging the structure of pixels or electrical wiring.

According to various embodiments, the camera module 400 at least partially penetrates the first through hole 301 and the second through hole 331 in the internal space of the electronic device 300 , and the front plate 320 . It may be arranged to detect the external environment through the camera exposure area 321 formed at the corresponding position of . According to one embodiment, the camera exposure area 321 is substantially at least one lens (eg, the first lens of FIG. 4 ) disposed on the barrel member (eg, the barrel member 420 of FIG. 4 ) of the camera module 400 . A transparent region facing the first region (eg, an effective region) of the lens 431 may be included. In another embodiment, the camera exposure area 321 may include a printing area having a predetermined width surrounding the transparent area.

The electronic device according to various embodiments disclosed in this document may have various types of devices. The electronic device may include, for example, a portable communication device (eg, a smart phone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, or a home appliance device. The electronic device according to the embodiment of the present document is not limited to the above-described devices.

Various embodiments of the present invention disclosed in this specification and drawings and terms used therein are not intended to limit the technical features described in this document to specific embodiments, and include various modifications, equivalents, or substitutions of the embodiments. should be understood as

Claims (12)

1. An aluminum alloy for die casting thin products, comprising:

   Based on the total weight of the alloy, 9.0 wt% or more and 11.0 wt% or less of silicon (Si), 1.0 wt% or more and 1.3 wt% or less of magnesium (Mg), 0.0001 wt% or more and 0.9 wt% or less of iron (Fe), 0.0001 wt% or more and less than 0.1 wt% copper (Cu), more than 2.0 wt% and 3.0 wt% or less zinc (Zn), strontium (Sr) in an amount satisfying the following content ratio of strontium (Sr), and the remaining amount of aluminum (Al) containing,

   The content ratio of the strontium (Sr) is (weight% of Si - 1.74 × weight% of Mg): weight% of Sr = 200 to 1000: The range of 1, aluminum alloy for thin product die casting.
2. According to claim 1,

   The alloy is an aluminum alloy for thin-walled die casting, which contains manganese (Mn) in an amount of 0.0001 wt% or more and 0.25 wt% or less based on the total weight of the alloy.
3. According to claim 1,

   The alloy is an aluminum alloy for die casting thin products containing 0.35% by weight or more and 0.5% by weight or less of chromium (Cr) based on the total weight of the alloy.
4. According to claim 1,

   The alloy is an aluminum alloy for die-casting thin products containing 0.17% by weight or more and 0.25% by weight or less of titanium (Ti) based on the total weight of the alloy.
5. According to claim 1,

   The alloy is an aluminum alloy for die-casting thin products containing nickel (Ni) in an amount of 0.0001 wt % or more and 0.01 wt % or less based on the total weight of the alloy.
6. According to claim 1,

   The alloy is an aluminum alloy for die casting thin products containing 0.015% by weight or more and 0.035% by weight or less of tin (Sn) based on the total weight of the alloy.
7. According to claim 1,

   The alloy includes, based on the total weight of the alloy, 10.2 wt% or more and 10.7 wt% or less of silicon (Si), 1.05 wt% or more and 1.25 wt% or less of magnesium (Mg), and 0.0001 wt% or more and 0.9 wt% or less of iron (Fe), copper (Cu) of 0.0001 wt% or more and 0.005 wt% or less, zinc (Zn) of more than 2.0 wt% and 2.5 wt% or less, strontium (Sr) in an amount satisfying the following content ratios of strontium (Sr), 0.0001% or more and 0.01 wt% or less of nickel (Ni), 0.0001% or more and 0.25% or less of manganese (Mn), 0.35 wt% or more and 0.5 wt% or less of chromium (Cr), 0.17 wt% or more and 0.25 wt% or less of titanium ( Ti), 0.015 wt% or more and 0.035 wt% or less of tin (Sn), and the remaining amount of aluminum (Al),

   The content ratio of strontium (Sr) is (weight% of Si - 1.74 × weight% of Mg): weight% of Sr = 300-500: The range of 1, an aluminum alloy for thin product die casting.
8. According to claim 1,

   The alloy has a yield strength of 210 MPa or more, and an elongation of 2% or more, an aluminum alloy for thin product die casting.
9. A component for an electronic device made of the aluminum alloy for die casting of a thin product according to any one of claims 1 to 8.
10. 10. The method of claim 9,

    The electronic device component is a bracket mounted on a mobile electronic device.
11. An electronic device comprising the electronic device component of claim 9 .
12. In an electronic device,

    front plate,

    back plate, and

    a support plate on which at least some of the plurality of components of the electronic device are disposed;

    At least one of the front plate, the back plate and the support plate is made of an aluminum alloy for thin-wall product die casting,

    The aluminum alloy for die casting thin products,

    Based on the total weight of the alloy, 9.0 wt% or more and 11.0 wt% or less of silicon (Si), 1.0 wt% or more and 1.3 wt% or less of magnesium (Mg), 0.0001 wt% or more and 0.9 wt% or less of iron (Fe), 0.0001 wt% or more and less than 0.1 wt% copper (Cu), more than 2.0 wt% and 3.0 wt% or less zinc (Zn), strontium (Sr) in an amount satisfying the following content ratio of strontium (Sr), and the remaining amount of aluminum (Al) containing,

    The content ratio of the strontium (Sr) is (weight% of Si - 1.74 × weight% of Mg): weight% of Sr = 200 to 1000: the range of 1, the electronic device.

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