JPH034138A - Ultra-micro hardness tester - Google Patents

Abstract

PURPOSE:To accurately measure the dynamic hardness of a sample after correcting even the deflection of its own sample by calculating the dynamic hardness of the sample based on a specific expression. CONSTITUTION:The hardness meter is equipped with an indentator 5, an electro magnetic coil 6 which places a test load on the indentator 5, and a displacement detector 10 which detects the displacement of the indentator 5, and a CPU 18 which calculates the dynamic hardness DH0 of the sample by calculating a proportion constant K by a method of the least squares from an arithmetic equation DH0=alphaP/d0<2>=P/(d-KP)<2>, where P is the load placed on the indentator 5 by the electromagnetic coil 6, (d) the displacement of the indentator 5 detected corresponding to the load, d0 real penetration depth, K the displacement load proportion coefficient in loading, alpha a constant determined according to the shape of the indentator 5, and DH0 the dynamic hardness. Then a displacement quantity detected by the displacement detector 10, i.e. the movement quantity detection signal of the indentator 5 is amplified 15, A/D-converted 17, and sent to and processed by a CPU 18 to obtain the dynamic hardness of the sample. Consequently, the dynamic hardness of the sample can accurately be measured after the deflection of the sample itself is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [A Field of Application of Togami] The present invention relates to a hardness meter that applies a test load to an indenter and determines the hardness of the sample from the depth of indentation of the indenter into the sample surface at that time.

[Conventional technology] In a hardness tester that measures hardness from the indentation depth of an indenter, a preset load is applied to the indenter and the indenter is injected into the sample surface, and the displacement after the indenter contacts the sample surface is calculated as the indentation depth. The sample hardness is calculated as follows. In this case, since the mechanical deflection of the loading system due to the load is reproducible, preliminary measurements or tests are performed to determine the proportionality coefficient for these displacements/loads, and this coefficient is used to calculate the hardness value. is being corrected.

[Problem to be Solved by the Invention 1] However, in actual hardness measurement, the sample itself is deflected, and especially in ultra-low load type ultra-micro hardness meters, the deflection of the sample itself is a problem.

There was a problem in that no corrective measures were taken for this deflection. In other words, the deflection of the sample changes depending on the conditions when it is attached to the sample stage, so when it is attached using adhesive or when testing a sample with a hard surface layer and a soft interior, the deflection of the sample itself may change. If this is not corrected, accurate hardness cannot be calculated.

[Means for Solving Problem B] In order to solve the above problem, the present invention employs the following configuration.

That is, the hardness tester according to the present invention includes an indenter, a loading means for applying a test load to the indenter, and an indenter displacement amount detection means for detecting displacement of the indenter, and the hardness tester includes an indenter, a loading means for applying a test load to the indenter, and an indenter displacement amount detecting means for detecting displacement of the indenter, and the hardness tester comprises an indenter, a loading means for applying a test load to the indenter, and an indenter displacement amount detecting means for detecting displacement of the indenter. P, the displacement of the indenter detected in response to this load is d, the true indentation depth is do, the displacement load proportional constant when the load is applied is α, the constant determined by the shape of the indenter is dynamic When hardness is DHo, DH,=αP/d.

=P/(d-KP)2 Based on the calculation formula, the proportionality constant K is calculated by the least squares method, and a calculation means is provided for calculating the dynamic hardness DH of the sample. .

[Function] In general, the dynamic hardness DH, of a sample is expressed as DH,=QP/do'(
a is a constant due to the indenter), and the displacement is used to correct mechanical deflection included in the indentation depth d of the measured indentation, deflection of the sample, deflection of the adhesive resin 1 layer when mounting the sample, etc. If the load proportionality constant is d, then d is
0=d- becomes P.

Therefore, using the formula DH, = αP/ (d-KP)2, the true dynamic hardness D is determined by the least squares method from the load and indenter displacement data at any measurement point after the start of the test.
Ho is required.

[Example] FIG. 1 is a diagram showing the configuration of an apparatus according to an embodiment of the present invention.

This hardness tester is configured as an ultra-micro hardness tester, and a loading device 1 in a frame 20 is equipped with an indenter 5 at one end of a balance 2 whose central part is supported by a knife 3, and an electromagnetic at the other end. It is configured as a variable load device provided with an iron core 7 that generates electromagnetic force in cooperation with a coil 6. The indenter 5 is attached to the tip of a balance rod 8 provided on the top l\2,
A differential transformer type displacement detector IO is provided above the indenter 5 to detect the amount of displacement of the indenter 5.

The load bag gt increases or decreases the load by the electromagnetic force of the electromagnetic coil 6 generated by the load current supplied from the load current supply device 16, and is designed to increase or decrease the load on the sample stage 13. Sample dish 4
The load transmitted to the indenter via the indenter can be increased, decreased, or stopped at will. Therefore, by unbalancing the balance and measuring the load current supplied when the indenter 5 is pushed into the sample surface, the load at the time of loading can be measured in real time.

While the load is being applied, displacement on the surface of the sample 14 pressed by the indenter 5 is detected by the displacement detector 10. The displacement amount detected by the displacement detector, that is, the movement amount detection signal of the indenter 5 is amplified by the amplifier l115, and
/D conversion 12117 and sent to CPU. Therefore, displacement under a certain load is also measured in real time. These load and displacement data are stored in the RAM 20, and are processed by the CPU 18 as described later to determine the hardness of the sample. In addition, the indentation depth vs. load curve shown in FIG.
．． drawn by.

The CPU 18 is a basic formula for determining the true dynamic hardness DHo based on load and displacement data.

DH, = αP/do' = aP/(P on d-)・-(
1) Perform arithmetic processing as follows. Here, α is a constant determined by the shape of the indenter, P is the load weight (gf), d is the measured displacement value, and do is the true indentation depth. This is a displacement load proportionality constant that corrects the deflection of the adhesive resin layer of the adhesive part. Therefore, as shown in Fig. 3, the true indentation depth do can be found by subtracting the deflection P from the measured value d (d, = d
- to P).

The calculation method is explained below.

First, from equation (1), 2P2-2KPd-(α/DH,)P+d2=O-(
2) Therefore, 2ΣP2=2 ΣPd−(α/D HO)ΣP+Σ
d2:0・−(3) to 2ΣP2d−2 to 2ΣPd2 −(α/D)1. ) ΣPd+Σd3=o-(4) Based on the minimum desperation method, from equations (3) and (4), from data P and d at any measurement point, ΣP, Σp2. ΣPd, Σ
Pd', Σd2. Calculate Σd3, etc., approximate the depth-load curve quadratically, and use the coefficient of the quadratic term as a proportionality constant to calculate the hardness D.
Calculate H0.

1. There are two solutions of 2, but the one with the condition that D) 10 is positive is selected.

Although there is no calculation method other than this calculation method, it is also possible to calculate from the following two load conditions of Pl and P2 using the following equations (5) and (6).

2P, 22 P+d+ (α/DH,)P, +dl"=O-(5) p2'-2
P2 d2 − (α/D) (o ) P2 + d2”: Qm (6)
In this way, according to the above-mentioned example device, the true indentation depth is determined by correcting the deflection of the mechanical system of the load section, the deflection of the sample stage, the deflection of the adhesive resin layer in the sample mounting section, the deflection of the sample itself, etc. The dynamic hardness of the sample can be determined accurately. It is also possible to measure the surface hardness of a sample with a soft interior, and to correct the amount of elastic deformation inside the sample.

[Effects of the Invention] As is clear from the above description, the hardness meter according to the present invention makes it possible to accurately determine the dynamic hardness of a sample after also correcting the deflection of the sample itself. In addition, it has become possible to accurately measure the surface hardness of samples that have a hard surface layer and a soft interior.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the configuration of an ultra-microhardness meter that is an embodiment of the present invention, Fig. 2 is a diagram showing the indentation depth vs. load curve in the embodiment, and Fig. 3 is a diagram explaining the correction formula. It is. 1... Loading device 2... Balance 5...-Indenter 6.
・・Electromagnetic coil (load generation means) lO・-Displacement detection 5
18-PCI (hardness value calculation means) Figure 2

Claims (1)

[Claims] (1) comprising an indenter, a loading means for applying a test load to the indenter, and an indenter displacement amount detection means for detecting displacement of the indenter;
The load applied to the indenter by the load means is P, the displacement of the indenter detected in response to this load is d, the true indentation depth is d_o, the displacement load proportionality constant when the load is applied is K, and the shape of the indenter is The constant thus determined is α, and the dynamic hardness is DH.
When _o, the proportionality constant K is calculated by the least squares method based on the formula DH_o=αP/d_o^2 =P/(d-KP)^2, and the dynamic hardness DH_o of the sample is calculated. A hardness meter characterized by being provided with a calculation means.