CN101440441B

CN101440441B - Method for thinning CaMgSn phase in Mg-Sn-Ca magnesium alloy by adding Y

Info

Publication number: CN101440441B
Application number: CN2008102372164A
Authority: CN
Inventors: 潘复生; 汤爱涛; 杨明波
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2008-12-23
Filing date: 2008-12-23
Publication date: 2010-08-25
Anticipated expiration: 2028-12-23
Also published as: CN101440441A

Abstract

The invention relates to a method for thinning a CaMgSn phase in Mg-Sn-Ca series magnesium alloy by adding Y, which is achieved through adding the rare-earth element Y into the Mg-Sn-Ca series magnesium alloy. The method comprises: under protection of fusing agent or gas, blending and melting the Mg-Sn-Ca magnesium alloy according to corresponding component proportion, heating the magnesium alloy to between 720 and 740 DEG C, and then adding Mg-Y middle alloy into the magnesium alloy, wherein the adding amount of Mg is 17 weight percent, and the adding amount of Y is 0.5 to 1.5 weight percent of total weight of the furnace materials. The method can thin the crude CaMgSn phase in the Mg-Sn-Ca series magnesium alloy, and improves performance of the Mg-Sn-Ca series magnesium alloy.

Description

The method that adds CaMgSn phase in the Y refinement Mg-Sn-Ca series magnesium alloy

Technical field:

What the present invention relates to is the method for CaMgSn phase in a kind of Y of adding refinement Mg-Sn-Ca series magnesium alloy, belongs to class of metal materials and field of metallurgy.

Background technology:

Magnesium alloy is as the commercial metal engineering structured material of light-weight, falls because of it has light specific gravity, specific tenacity specific rigidity height, damping vibration attenuation that dry ability is strong, liquid condition shaping superior performance and be easy to advantage such as recycling, is described as 21 century " green structured material ".But at present because the high-temperature creep resistance of existing magnesium alloy is poor, the long term operation temperature can not surpass 120 ℃, makes it can't be used for making to the demanding vehicle transmission parts of high temperature creep property, has therefore greatly hindered the further application of magnesium alloy.Also just because of like this, both at home and abroad given great attention with the research and development of heat resistance magnesium alloy, and serial heat resistance magnesium alloy such as Mg-Al-Si, Mg-Al-RE, Mg-Al-Ca, Mg-Al-Ca-RE, Mg-Al-Sr, Mg-Al-Sn, Mg-Zn-Al, Mg-Zn-RE, Mg-Zn-Si, Mg-Zn-Sn and Mg-Sn-Ca has been studied in trial-production successively for automobile with high-temperature creep resistance.Obtained manufacturing experimently in the heat resistance magnesium alloy of research at these, the Mg-Sn-Ca series magnesium alloy since have high-temperature behavior better, the advantage of aspect such as cost is lower and corrosion resistance is good, be considered to a kind of rising high temperature and creep resistance magnesium alloy of new generation.Compare with other heat resistance magnesium alloys, the heat-resisting strengthening mechanism of Mg-Sn-Ca series magnesium alloy mainly is to realize mutually at crystal boundary and intracrystalline formation CaMgSn with Ca by introducing low-cost alloying element Sn.Because CaMgSn is at quite stable below 300 ℃, thereby make the Mg-Sn-Ca series magnesium alloy have higher high-temperature creep resistance.Also see the advantage that the Mg-Sn-Ca series magnesium alloy is had just, thus recent years people be that the research and development of heat resistance magnesium alloy has given to pay close attention to widely and the attention of height to Mg-Sn-Ca, and this has been carried out positive research.Find by inquiry that as Huang etc. Mg-5Sn-2Ca and Mg-3Sn-2Ca ternary magnesium alloy can reach 82.5h and 358.4h respectively in the creep life under 135 ℃ and the 85MPa condition, its corresponding secondary creep speed is respectively 3.5 * 10 ^-8s ^-1With 4.5 * 10 ^-9s ^-1, demonstrated very high high-temperature creep resistance [Yuanding Huang, NorbertHort, Tarek Abu Leil1, Karl Ulrich Kainer and Yilin Liu, Key Engineering Materials, 2007,345-346:561-564].Although carried out certain research for the Mg-Sn-Ca series magnesium alloy both at home and abroad at present, its apply still because of the comprehensive mechanical property of alloy relatively poor etc. former thereby be subjected to a certain degree restriction.As mentioned above, the heat-resisting strengthening mechanism of Mg-Sn-Ca series magnesium alloy mainly is to realize mutually at crystal boundary and intracrystalline formation CaMgSn with Ca by introducing low-cost alloying element Sn, but because that the CaMgSn that forms compares is thick, and thick CaMgSn meets and becomes formation of crack and cause the creep-resistant property of alloy to descend.Therefore, refinement CaMgSn is considered to one of key factor of improving Mg-Sn-Ca series magnesium alloy creep-resistant property mutually.As everyone knows, alloying and/or microalloying are one of effective ways of second phase in refinement and/or the rotten engineering alloy.But up to now, the research about thick CaMgSn phase in alloying and/or the microalloying refinement Mg-Sn-Ca series magnesium alloy yet there are no bibliographical information.

Summary of the invention:

The objective of the invention is to influences this deficiency of alloy property at existing Mg-Sn-Ca series magnesium alloy mutually because of there being thick CaMgSn, propose to adopt the method for alloying and microalloying, comprise its process for refining, to reach thick CaMgSn phase this purpose in the refinement Mg-Sn-Ca series magnesium alloy, thereby improve the performance of Mg-Sn-Ca series magnesium alloy, accelerate the industrial applications process of this series magnesium alloy.

To achieve these goals, the present invention proposes the method for thick CaMgSn phase in a kind of Y of adding refinement Mg-Sn-Ca series magnesium alloy, in the Mg-Sn-Ca series magnesium alloy, pass through to add the method for Mg-17%Y master alloy, come the thick CaMgSn phase in the refinement Mg-Sn-Ca series magnesium alloy, the adding of Y simultaneously also has the effect of reinforced alloys concurrently except that above-mentioned refining effect is arranged.

The method that the present invention proposes is as follows: under flux or gas shield, the Mg-Sn-Ca magnesium alloy is warmed up to 720-740 ℃ after by corresponding composition proportion fusing, adds the Mg-17wt.%Y master alloy; The per-cent that the Y add-on accounts for the furnace charge gross weight is 0.5-1.5wt.%, adding method: the Mg-17wt.%Y master alloy was toasted 15-30 minute at 100-150 ℃, with pressing wooden dipper to be pressed into the alloy liquid level rapidly following about 2-6 minute, be warmed up to 720-760 ℃ after the stirring then, use C then ₂Cl ₆Refining agent refining treatment 5-10 minute, the refining back that finishes is stirred alloy melt and was left standstill 10-15 minute at 740 ℃, leaves standstill to drag for surface scum after finishing, and casts then.

Adopt the mechanism of present method refinement CaMgSn phase to be that Y element has the atomic radius (Ce:0.182nm bigger than the Sn element; Sn:0.141nm).When add Y in the Mg-Sn-Ca magnesium alloy after, it can be in the solid-liquid interface enrichment in process of setting, thereby hinders the Sn atomic diffusion, and finally causes the refinement of CaMgSn phase.In addition, if the Y content that adds higher (as 〉=1.0wt%), also can in alloy, form the MgSnY phase, and the formation of this phase can consume some Sn on the one hand, this is mutually also owing to have higher thermostability on the other hand, it can hinder the growth of CaMgSn phase in process of setting, thereby makes CaMgSn obtain further refinement mutually.

Description of drawings:

Figure 1A and Figure 1B are respectively the microstructure pictures of Mg-3Sn-2Ca and Mg-3Sn-2Ca-0.5Y;

Fig. 2 A and Fig. 2 B are respectively the microstructure pictures of Mg-4Sn-1.5Ca and Mg-4Sn-1.5Ca-1.5Y;

Fig. 3 A and Fig. 3 B are respectively the micro-metallographic structure pictures of Mg-5Sn-2.5Ca and Mg-5Sn-2.5Ca-1.0Y.

Embodiment:

Below by concrete three embodiment technical scheme of the present invention and effect are further elaborated.

Embodiment 1: 2 ^#Under the flux protection, the Mg-3Sn-2Ca magnesium alloy is pressed 94.5wt.%Mg, be warmed up to 740 ℃ after the composition proportion fusing of 3wt.%Sn and 2wt.%Ca, add the Mg-17wt.%Y master alloy, the add-on of Y is the 0.5wt.% that is of furnace charge gross weight.Adding method: at 150 ℃ the Mg-17wt.%Y master alloy was toasted 20 minutes, with pressing wooden dipper to be pressed into the alloy liquid level rapidly following about 3 minutes, be warmed up to 740 ℃ after the stirring then, use C then ₂Cl ₆Refining agent refining treatment 5 minutes, the refining back that finishes is stirred alloy melt and was left standstill 10 minutes at 740 ℃, leaves standstill to drag for surface scum after finishing, and casts into then in the metal mold that is preheating to 100-150 ℃.

Embodiment 2: 2 ^#Under the flux protection, the Mg-4Sn-1.5Ca-0.25Mn magnesium alloy is pressed 92.75wt.%Mg, 4wt.%Sn, 1.5wt.%Ca and 0.25wt.%Mn composition proportion fusing after be warmed up to 720 ℃, add the Mg-17wt.%Y master alloy.The add-on of Y is the 1.5wt.% of furnace charge gross weight.Adding method: at 150 ℃ the Mg-17%Y master alloy was toasted 20 minutes, with pressing wooden dipper to be pressed into the alloy liquid level rapidly following about 3 minutes, be warmed up to 740 ℃ after the stirring then, use C then ₂Cl ₆Refining agent refining treatment 5 minutes, the refining back that finishes is stirred alloy melt and was left standstill 10 minutes at 740 ℃, leaves standstill to drag for surface scum after finishing, and casts into then in the metal mold that is preheating to 100-150 ℃.

Embodiment 3: at C0 ₂Protection is pressed 91.5wt.%Mg with the Mg-5Sn-2.5Ca magnesium alloy down, is warmed up to 740 ℃ after the composition proportion fusing of 5wt.%Sn and 2.5wt.%Ca, adds the Mg-17%Y master alloy.The add-on of Y is the 1.0wt.% of furnace charge gross weight.Adding method: at 150 ℃ the Mg-17wt.%Y master alloy was toasted 20 minutes, with pressing wooden dipper to be pressed into the alloy liquid level rapidly following about 3 minutes, be warmed up to 740 ℃ after the stirring then, use C then ₂Cl ₆Refining agent refining treatment 5 minutes, the refining back that finishes is stirred alloy melt and was left standstill 10 minutes at 740 ℃, leaves standstill to drag for surface scum after finishing, and casts into then in the metal mold that is preheating to 100-150 ℃.

With above three embodiment and do not add the composition of Mg-Sn-Ca magnesium alloy of Y and fabric analysis and The performance test results as shown in table 1.Comparative analysis result from table 1 can see that behind a certain amount of Y of adding, the mean sizes of CaMgSn phase obviously reduces in the alloy structure in the Mg-Sn-Ca series magnesium alloy.Simultaneously, the tensile property of alloy and creep property are improved.

Claims

1. method that adds CaMgSn phase in the Y refinement Mg-Sn-Ca series magnesium alloy, described method are to realize that by add rare earth element y in the Mg-Sn-Ca series magnesium alloy per-cent that the add-on of rare earth element y accounts for the furnace charge gross weight is 0.5-1.5wt.%; Described method is under flux or gas shield, is warmed up to 720-740 ℃ after the Mg-Sn-Ca magnesium alloy is melted by corresponding composition proportion, adds the Mg-17wt.%Y master alloy; The per-cent that the Y add-on accounts for the furnace charge gross weight is 0.5-1.5wt.%, adding method: the Mg-17wt.%Y master alloy was toasted 15-30 minute at 100-150 ℃, with pressing wooden dipper to be pressed into the following 2-6 of alloy liquid level minute rapidly, be warmed up to 720-760 ℃ after the stirring then, use C then ₂Cl ₆Refining agent refining treatment 5-10 minute, the refining back that finishes is stirred alloy melt and was left standstill 10-15 minute at 740 ℃, leaves standstill to drag for surface scum after finishing, and casts then.

2. the method that adds CaMgSn phase in the Y refinement Mg-Sn-Ca series magnesium alloy according to claim 1; it is characterized in that: described method is under flux or gas shield; the Mg-Sn-Ca magnesium alloy is warmed up to 740 ℃ after by the fusing of corresponding composition proportion; add the Mg-17wt.%Y master alloy; the per-cent that the Y add-on accounts for the furnace charge gross weight is 0.5-1.5wt.%; adding method: the Mg-17wt.%Y master alloy was toasted 20 minutes at 150 ℃; then with pressing wooden dipper to be pressed into the alloy liquid level rapidly following 3 minutes; be warmed up to 740 ℃ after the stirring, use C then ₂Cl ₆Refining agent refining treatment 5-10 minute, the refining back that finishes is stirred alloy melt and was left standstill 10 minutes at 740 ℃, leaves standstill to drag for surface scum after finishing, and casts then.