CN105483401A

CN105483401A - Preparing method for Al-Cu-Ni-Mg alloy with addition of Si element

Info

Publication number: CN105483401A
Application number: CN201410475884.6A
Authority: CN
Inventors: 李娜
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-09-18
Filing date: 2014-09-18
Publication date: 2016-04-13

Abstract

The invention provides a preparing method for an Al-Cu-Ni-Mg alloy with the addition of a Si element. A technological process of burdening, smelting, modification, degassing and drossing, pouringand solution-aging treatment is adopted, the Si elementsofdifferent contents areadopted, and therefore the normal-temperature performance and the high-temperature performance of the Al-Cu-Ni-Mg alloy can be improved; and particularly, when the mass fraction of the added Si element is 12%, the effect is obvious, and the good comprehensive performance is achieved.

Description

A kind of preparation method adding the Al-Cu-Ni-Mg alloy of Si element

Technical field

The invention belongs to field of material technology, particularly relate to a kind of preparation method adding the Al-Cu-Ni-Mg alloy of Si element.

Background technology

The features such as Al-Cu-Ni-Mg alloy has density and thermal expansivity is little, dimensional stabilizing, wear resistance are good, are therefore widely used in the industries such as automobile, motorcycle, aerospace and household electrical appliances.Current domestic and international most of car cylinder cap has adopted aldural to produce, and aluminum alloy cylinder cover replaces Cast Iron Cylinder Head rapidly.Select there is AC in the material of cylinder cap ₄b, 328, A-S ₅u ₃with ZL101, ZL104 and ZL107 alloy etc.Above-mentionedly be hypoeutectic Al-Cu-Ni-Mg alloy, particularly hot strength is lower for their intensity, hardness is relatively not high, specific tenacity is lower, castability and anti-fatigue performance general, require higher cylinder cap to some comprehensive mechanical properties, can not satisfy the demands, its normal temperature and high-temperature behavior are badly in need of improving.

Summary of the invention

The technical problem to be solved in the present invention is: a kind of preparation method adding the Al-Cu-Ni-Mg alloy of Si element, to solve the technical problem of Al-Cu-Ni-Mg Alloy At Room Temperature and high-temperature behavior poor performance.

1. the technical solution used in the present invention is: a kind of preparation method adding the Al-Cu-Ni-Mg alloy of Si element, is characterized in that: comprise the following steps:

(1) prepare burden: in Al-Cu-Ni-Mg alloy, add the Si that massfraction is 7% ~ 12.8%.

(2) melt: the furnace charge prepared is placed in plumbago crucible, melts in well formula crucible oven, temperature of fusion is 760 DEG C, insulation is until all melt.

(3) temperature is reduced to 720 DEG C, after Mg press-in being stirred with bell jar, leave standstill 20min.

(4) select P+RE to carry out compound modification treatment, adding massfraction content is leave standstill 30min after the red phosphorus salt of 0.1% and the RE of 0.5% carry out composite inoculating.

(5) with 0.4% C ₂cl ₆divide and carry out degasification 3 times, skim after leaving standstill 20min.

(6) molten metal is poured in the metal mold being preheated to 200 DEG C.

(7) solution treatment: (530 ± 5) DEG C × 5h and water-cooled, 60 ~ 100 DEG C → ageing treatment (200 ± 5) DEG C × 10h → air cooling.

Above-mentioned steps (1) Si content is 12%.

Beneficial effect of the present invention: compared with prior art, beneficial effect is as follows:

(1) along with the raising of Si content, normal temperature, 250 DEG C of Testing Tensile Strength at Elevated Temperatures of engine cylinder cover casting Al-Cu-Ni-Mg alloy first raise, and rear reduction, reaches maximum value near eutectic point.

(2) when Si content is less than 10%, along with the raising of Si content, alloy rigidity rises to some extent; When Si content is in pseudoeutectic district and hypereutectic district, firmly crisp primary silicon can be produced, the hardness of alloy is significantly improved.

(3), when Si content is 12%, good alloy low temperature, high-temperature comprehensive property can be obtained.

Embodiment

Embodiment: a kind of preparation method adding the Al-Cu-Ni-Mg alloy of Si element, is characterized in that: comprise the following steps:

(6) molten metal is poured in the metal mold being preheated to 200 DEG C.

Above-mentioned steps (1) Si content is 12%.

Adopt the preparation method of the Al-Cu-Ni-Mg alloy of the above-mentioned a kind of Si of interpolation element can draw the impact of Si content on Al-Cu-Ni-Mg alloy at normal temperature tensile strength, as table 1 can be found out, along with the increase of Si content, room temperature tensile strength first increases rear reduction, near eutectic point, reach maximum value.When Si content is in 7.0% ~ 12.8% scope, the increase of Si content can increase the modulus of strain hardening of lower strain area, puies forward heavy alloyed tensile strength; By rotten, T6 thermal treatment, in alloy, Mg can be generated ₂si, AL ₂cuMg, W phase (AlxMg ₅si ₄cu ₄), Q phase (Al ₅mg ₈cu ₂si ₆) etc. dispersion-strengthened phase.These mostly are firmly crisp intermetallic compound mutually, play a part equally in the alloy to hinder dislocation motion, thus can produce superfluous strengthening phase.Along with the increase of Si content, the superfluous phase amount in Al-Cu-Ni-Mg alloy increases, and alloy strength improves.On the other hand, in the alloy, inevitably have a small amount of Fe and enter liquation, can Al be generated ₃the membership that adds of Fe, Ni makes Al ₃fe melts, and generates tiny Al9FeNi phase simultaneously, thus puies forward heavy alloyed intensity.When Si content exceedes eutectic point, thick, firmly crisp primary silicon can be produced, even if rotten, also can only change its pattern and size, and its quantity can not be made to reduce.Along with the increase of Si content, crystallization range becomes large, and the loose tendency of alloy strengthens, and resistance to air loss reduces, and hydrogen solubleness in the alloy reduces simultaneously, causes alloy strength to reduce thus.

Table 1, Si content is on the impact of room temperature tensile strength

Content	4	7	9	12	15	18
							Intensity/MPa	232	240	268	293	250	221

Adopt the preparation method of the Al-Cu-Ni-Mg alloy of the above-mentioned a kind of Si of interpolation element can draw the impact of Si content on Al-Cu-Ni-Mg alloy high-temp tensile strength, if table 2 is that different Si content is on the impact of Al-Cu-Ni-Mg alloy high-temp tensile strength.Can find out, along with the increase of Si content, Testing Tensile Strength at Elevated Temperature first increases and then reduces, near eutectic point, reach maximum value.Concerning Al-Cu-Ni-Mg alloy, it strengthens the strengthening of mainly superfluous phase (Si crystal).Along with the increase of Si content, the superfluous phase amount produced in aluminium alloy will increase, and the hot strength of alloy also can improve accordingly; On the other hand, due to adding of Ni, Al can be generated in the alloy ₆cu ₃ni, Al(CuNi) ₂deng strengthening phase, its high-temperature behavior of corresponding raising.When Si content reaches hypereutectic territory, the surplus of generation is too much mutually, and the intensity of alloy declines on the contrary; Simultaneously in hypereutectic region, produce thick, firmly crisp primary crystal Si, the decline of hot strength.

Table 2, Si content is on the impact of 250 DEG C of Testing Tensile Strength at Elevated Temperatures

Content	4	7	9	12	15	18
							Intensity/MPa	103	141	144	171	137	122

Adopt the preparation method of the Al-Cu-Ni-Mg alloy of the above-mentioned a kind of Si of interpolation element can draw the impact of Si content on Al-Cu-Ni-Mg alloy elongation, if table 3 is that different Si content is on the impact of Al-Cu-Ni-Mg alloy elongation.As can be seen from Table 3, the elongation of alloy is higher when hypoeutectic is interval.Because when Si content exceedes eutectic point, can generate primary silicon in alloy, primary silicon is hard crisp phase, causes the moulding reduction of alloy.As can also be seen from Table 3, although the change of Si content causes the change of alloy elongation, due to the performance of casting Al-Cu-Ni-Mg alloy itself, alloy is made to have higher normal temperature and high temperature elongation.

Table 3, Si content is on the impact of Al-Cu-Ni-Mg alloy elongation

Content	4	7	9	12	15	18
							Normal temperature unit elongation/%	3.9	6.2	3.1	3.0	2.5	1.9
High temperature unit elongation/%	12.1	17.6	14.1	14.0	11.2	7.7

Adopt the preparation method of the Al-Cu-Ni-Mg alloy of the above-mentioned a kind of Si of interpolation element can draw the impact of Si content on Al-Cu-Ni-Mg alloy at normal temperature hardness, table 4 is impacts of Si content alloy hardness.Owing to there is pseudoeutectic district, so will primary silicon be produced in this pseudoeutectic district.As can be seen from Table 4, when Si content is less than 10%, main alloying component is Al matrix and eutectic Si, and the increase of eutectic Si and a small amount of strengthening phase can make the hardness of alloy promote to some extent.When pseudoeutectic district and hypereutectic district, can produce firmly crisp primary silicon, the existence of primary silicon can make the hardness of alloy significantly improve.

Table 4, Si content is on the impact of Al-Cu-Ni-Mg alloy rigidity

Content	4	7	9	12	15	18
							Hardness/HBS	92	95	101	121	129	143

Claims

1. add a preparation method for the Al-Cu-Ni-Mg alloy of Si element, it is characterized in that: comprise the following steps:

(1) prepare burden: in Al-Cu-Ni-Mg alloy, add the Si that massfraction is 7% ~ 12.8%;

(2) melt: the furnace charge prepared is placed in plumbago crucible, melts in well formula crucible oven, temperature of fusion is 760 DEG C, insulation is until all melt;

(3) temperature is reduced to 720 DEG C, after Mg press-in being stirred with bell jar, leave standstill 20min;

(4) select P+RE to carry out compound modification treatment, adding massfraction content is leave standstill 30min after the red phosphorus salt of 0.1% and the RE of 0.5% carry out composite inoculating;

(5) with 0.4% C ₂cl ₆divide and carry out degasification 3 times, skim after leaving standstill 20min;

(6) molten metal is poured in the metal mold being preheated to 200 DEG C;

(7) fixation rates: solution treatment (530 ± 5) DEG C × 5h and water-cooled, 60 ~ 100 DEG C → ageing treatment (200 ± 5) DEG C × 10h → air cooling.

2. the preparation method of a kind of Mg-Zr-V alloy as described in claim 1, is characterized in that: described step (1) Si content is 12%.